A/N: So here's the third part that you've requested. I hope it was worth the wait! Tell me if you want a part four.

Warning(s): some talk about "the birds and the bees"

The day had come. It was Caden's fourth birthday.

To say you were a bit emotional was an understatement. Although he was still very young, you couldn't help but feel like he was growing up too fast. It felt like just the previous day you had given birth to your beautiful son and held him in your arms for the first time.

You hadn't planned a big party. Few of Caden's friends, and their parents, were coming over. Later on you would visit the Avengers. You just didn't want the other kids to swoon over your team mates. They were used to seeing you but if Thor showed up, for example, they'd lose their minds. You wanted to make sure that didn't happen.

Caden was sitting on the couch in your living room, fidgeting in excitement with his party hat on as he waited for his quests to arrive.

You, yourself, were in the bathroom, checking to see if your makeup was okay and if your hair was still neatly done. This was one of the few times you actually put in a lot of effort to look nice. It was Caden's birthday and your day off, so no need to wear your workout clothes or zipping up your catsuit and fly off to who knows where. No missions, no training. Just some time off.

As the door bell rang you looked at Caden from the reflection of the mirror, seeing him jump up from the couch and run to the door. You quickly followed behind. You opened the door and let the quests in. You welcomed them to your home and exchanged some words with the parents as the kids went off to play together.

After a few minutes the other invitees arrived and you mentally prepared for the dreaded discussion about your single life with the other parents. You were the only single parent in the group. The parents of Caden's friends were all happily together, been married for several years.

You let out a long exhale as you neared the kitchen where the other parents were drinking their coffee. You passed the living room and heard Caden call out for you. "Mommy! Come tell us a story."

You shrugged, Better than answering questions about my love life, you thought to yourself. You really dreaded those conversations. Questions being shot at you after another, it made you feel uneasy. They were way too invested in your love life. "Sure, sweetie." You smiled.

All the kids were sitting on the floor in a circle, playing with their toys and you sat down next to Caden, who snuggled up closer to you. "What kind of story do you want to hear?"

"Avengers story!" One of the kids called. You chuckled and started telling them a story about one of your missions. Nothing too violent, though. They were still very young...

***

When you were done, you bowed as the kids clapped. "Thank you," you smiled. "I'll leave you kids to play now." You said and kissed the top of Caden's head before continuing your way to the kitchen. Here we go, you thought to yourself and sighed.

You heard laughter coming from the kitchen as you neared it, chattering filled the not so roomy kitchen. "Oh, Y/N! Looks like the kids kept you busy. Sorry about that, the kids just really love to hear those heroic stories."

"Oh don't worry about it. I love telling them." You assured and poured a cup of coffee for yourself. "So what's up?"

"Oh, we were just talking about Rick and Gina. Their tenth wedding anniversary is coming up!"

"Ten years of marriage... Congratulations."

"Thank you." Said Gina.

"Ten years of being married, thirteen years of being together, still can't get enough of this woman." Rick smiled widely and snug an arm around Gina's waist, pulling her for a quick kiss.

You smiled at the two. Their love inspired you. Thirteen years of being together and they still couldn't keep their hands away from one another. You wished you could have had that too.

"So, Y/N. How's your love life?"

You rolled your eyes which made the others laugh. "Why do we always end up talking about this?"

"Come on, you're the only single one! You're young and beautiful. Are you telling me there is no one special in your life?"

You dropped your head down to look at your coffee cup, avoiding eye contact as a smile crept upon your lips.

"There is!" Laura squealed. "Oh, look at you. You're blushing!" She cooed as she pinched your cheeks.

You shoved her hands away but couldn't stop smiling, "Laura, please."

"Tell us!"

"Okay, nothing has really happened yet. But there's been some flirting back and forth." You shrugged and took a sip of coffee, waiting to be bombarded with a series of questions.

"How long have you known him?"

"Does he know about Caden?"

"How does he feel about you having a son?"

"How much money does he have?"

"Ellen!" You scolded.

She lifted her hands up in a sign of surrender. "Sorry! But money is important. Why do you think I married a doctor?" She joked and laid her head on her husband's shoulder.

"Because you committed an insurance fraud. When you got caught, I told you I wouldn't tell anyone if you went out on a date with me."

"You were such an ass, Mark." Ellen laughed. "But also charming as hell."

"Swept you off of your feet. Or foot, since you were clumsy enough to get your ankle broken."

"I blame the city for the slippery streets!"

"Of course you do, sweetheart." Mark mumbled and kissed the side of Ellen's head.

There were so many great couples around you who loved each other to death. Oh, how you wished you could have been one of those couples.

"Why don't we get started on that cake and call the kids in here to eat some?"

Your eyes widened, you slapped your palm on your forehead. "Oh, the cake." You muttered. "I'm sorry I have to make a phone call." You excused yourself and went to your bedroom to have a conversation in peace.

You knew just the person to call when you needed something in a short period of time.

Pietro.

You waited for only few seconds when he picked up his phone. "Hello?"

"Pietro! Hi, listen... I forgot to pick up the cake for Caden's birthday party. Do you happen to have the time to go pick it up and bring it to me? I'd owe you."

"Uhm... Now is really not a good time. But I'll send someone else. The cake should arrive in about 30 minutes." He said.

"Okay, thank you."

"You still owe me." You could practically hear Pietro smiling on the other end of the line.

"Yeah? For what?"

"For the other times I've been your delivery boy. So how about some cake—" You hung up before he could finish the sentence.

You walked back to the kitchen and told the other parents that the cake should be there in about a half an hour. The kids could wait that long, for sure.

"Now tell us about the guy."

Sigh.

***

You heard the sound of your doorbell and quickly jogged over and opened the door, expecting to see one of Stark's employees standing there with the cake you needed to be picked up but your breath got caught up in your throat as you saw the man standing in front of you.

"Hi," Bucky said as he handed you the box he was holding. "Here's the cake." He furrowed his brows as you made no move to take the box. "Is everything alright?"

You shook yourself from your trance, you took notice of the tight, red henley he was wearing. You quickly adverted your gaze from his body and looked at the box, hurriedly taking it in your hands. "I just... Didn't expect to see you. I thought maybe Pietro would have asked Tony to send one of his employees." You shrugged. "Do you want to come in?" You asked as you stepped aside.

Bucky brought his hand up to the back of his neck and rubbed it, "I don't know..."

"Bucky!" Caden yelled and suddenly he was crashing his body against Bucky's legs.

"Hey buddy," Bucky greeted and patted the young boy's head. He crouched down to be in the same eye level with your son and smiled, "Happy birthday." And soon Caden was hugging him again, now he was hugging him back properly.

Bucky was about to stand up but Caden still kept his arms around Bucky's neck. "Carry me!" He yelled out and Bucky chuckled, nodding.

"Anything for the birthday boy." He said and stood up with Caden still in his arms. He turned to you, "Is it okay if I come in?"

"Wouldn't have asked if it wasn't." You smiled and waited for him to step inside before closing the door.

You noticed that Bucky held Caden up with his metal arm and was trying to pull the sleeves of his henley lower with his human hand to cover up the metal. You placed your hand on his human hand and he looked at you. You smiled and pushed his hand away gently. He didn't have to hide his metal arm. He had nothing to be ashamed of.

Bucky gave you a small smile and you swore you could feel his fingers starting to place themselves between yours until you heard a scream of a child.

Bucky looked in the direction of the sound with a terrified look on his face but soon he just looked confused as he felt someone, or someones, crashing against his body. He looked down and saw two kids, a girl and a boy, with huge smiles on their faces. Bucky lifted his gaze to meet yours again and the confused look on his face was enough to make you laugh. "This is Tate and Tanya," you decided to introduce them. "They're twins and few of Caden's friends. And that's Cole and Jim over there." you pointed at the two boys jumping on the couch.

"Bucky!"

"Show us your metal arm!"

Bucky was still looking at you in confusion. He raised his brow at you as if asking what the hell was going on. "Caden must have told them about you." You shrugged and looked at the twins attached to Bucky's legs. "Just show them your arm. They'll get a kick out of it." You nudged his shoulder with yours.

Bucky started moving towards the living room, the two kids still holding tight onto his legs. The children giggled and soon let go of him when Bucky sat down on the couch. He set Caden down on his lap and rolled up the sleeve covering his metal arm. The kids were fascinated and they all tried to climb onto the couch just to be closer to the arm.

You smiled and continued your way to the kitchen to serve the cake.

The adults were still conversing as you entered the room. "Oh, the cake is here." Laura took the cake from your hands and took it out of the box. She raised a brow as she eyed the cake. "Iron Man?" She asked you and you shrugged.

"He likes uncle Tony," you chuckled and took a look at the cake shaped like the Iron Man helmet. "It's pretty good, don't you think?"

"Hey, who's that?" Tom asked and pointed towards the living room.

You turned to look at Bucky sitting on the couch with the kids just examining his arm and asking him about it. "That's Bucky."

"That's Bucky?" Ellen asked as she ran to the doorway to get a better look. "The Bucky? Wow." She sounded surprised.

"What?"

"I thought, from what you told us, he'd be a little more... Classy or old fashioned."

You couldn't help but laugh.

"Wait is that—" Gina gasped. "Is that the Winter Soldier?" She whispered.

You shot a warning look towards her and shook your head. "No. That's Bucky."

"Seems to get along with the kids." Tom pointed out.

"Yeah he's a really nice guy. Great with Caden. Kids love him. So just—"

"Hi," you heard a voice right behind you. You jumped slightly and turned around to see Bucky smiling at you.

"Hi." You said with a breathy laugh.

"Where did you run off to?" Bucky smiled and turned his attention to the other people in the room. He quickly rolled down his sleeve to cover the metal again before shaking everyone's hand. "Hi, I'm James but you can call me Bucky." He introduced himself.

"Nice to meet you, Bucky."

Bucky smiled and came to your side again. "I should probably—"

"No! Stay, eat some cake." You grabbed his arm before he could walk away. "You came here all the way from the tower and you brought the cake! I'm not going to kick you out just like that."

"Kick me out? No, I was just—"

"Shush." You jutted your finger at him. "Sit down at eat some cake."

"You need to stop shushing me." Bucky muttered as you pushed him to sit down on one of the chairs. The others around you laughed at the two of you bickering with each other. "You can all sit down, I'll get the kids." You said and walked out of the kitchen.

You ushered the kids to the table and they sat down, Caden taking a seat next to Bucky and the other kids sat on their parents' laps. Your kitchen was pretty small, there wasn't much room for a bigger table.

You decided to take a picture of the cake before cutting it. Caden insisted on being in the picture as well and of course you didn't want to say no. So you took out your phone and took a picture before placing four candles on the cake, lighting them up. "Should we sing?" You asked and the kids nodded. You started singing happy birthday and everyone joined in. You crouched down next to Caden and whispered in his ear, "Make a wish." And you kissed him cheek. You continued to sing.

Caden closed his eyes and made fists with his small hands, squeezing them tightly as if that would have helped with making the wish come true. He opened his eyes, took a deep breath before blowing out every candle at the first attempt right as the song was over.

Everyone clapped and cheered. You were even shedding a few tears that got unnoticed by everyone else except Bucky. He placed his hand on your shoulder and you turned to look at him with tears in your eyes. He pulled you closer to him and you laid your head on his shoulder while you sat on the edge of the chair, almost falling off. "He's growing up so fast." You muttered.

"I know." Bucky muttered and rubbed your arm up and down, trying to comfort you. "Before you know it, you'll be dropping him off at school."

You elbowed his side and he whined. "Don't make me more upset."

"I'm sorry, doll." He kissed the side of your head which caused you to blush.

"Okay, let's cut the cake!" You stood up and started cutting pieces from it, serving it for everyone.

***

After eating, everyone except you and Bucky went to the living room. Caden started opening his presents and came to the kitchen every once in a while to show you what he got.

You were sat on the counter just talking to Bucky. You were supposed to do the dishes but talking to him was way more interesting. The dishes were in no rush to get cleaned anyway.

"So... Four years, huh?" Bucky asked.

"Don't." You groaned. "I don't want to start crying again." You chuckled.

"Four years of being a mother. Even more years to come."

You stiffled a laugh and raised your eyebrows at him. "Bucky?" He turned to look at you. "What are you getting at?"

He shrugged and gave you a sheepish grin. "Four years is a pretty long time and you've raised him all on your own. What about the years ahead of us? You think you can do that all by yourself?"

You scoffed, crossing your arms. "You don't think I can do this alone? I've done it for four years now I think I can handle it." You jumped off the counter and moved to the sink, deciding to do the dishes anyway.

"No! No, I just... I mean who's going to give him the birds and the bees talk when he's older? Shouldn't he have a man to tell him?"

"He doesn't need a man to tell him. I've had sex, I'll tell him exactly what needs to be told." You said as you washed the dishes, placing the plates on the drying cabinet over the sink.

"But shouldn't he know what it's like from the man's point of view?"

"Well shouldn't he know how to treat the woman he's going to be with?" You asked.

"Maybe he should hear it from both."

"Yeah, well... Who's he going to talk to besides me? Are you up for it?" You asked with a laugh.

He shrugged, "Sure, why not."

You looked at him wide eyed, completely forgetting the pile of dishes in the sink as you turned around fully towards him. "I was joking."

"I wasn't."

"Are you sure?"

"Yeah, we're best buds!"

"You think he'll still idolise you when he's a teenager?" You asked with a wide grin playing on your lips.

Bucky looked at you as if it was obvious, "Of course."

You couldn't help but laugh. "To be honest, I do too." You said honestly. "But are you sure you know everything that needs to be known about sex?"

"Oh, I know."

"I think I'll need some proof to be sure." You teased.

You hadn't even noticed that he had come to stand right in front of you. You saw his gaze flicker to your lips as he licked his own. He placed his hands on the counter behind you so his face was slightly closer to yours. He made no further move.

"Okay, are you ever actually going to kiss me or are you waiting for someone to interrupt us again?" You asked impatiently.

Bucky looked dumbfounded and he took a small step back. "What?" He asked which made you roll your eyes.

"You know, all these little scenarios we've been in. The lab, the gym and now this." You said as you waved your hand between the two of you. "You always lean in! But somehow there's always been an interruption." You sighed in frustration.

"I haven't leaned in!"

"Oh, yes you have." You fought back. "So? Are you ever going to do it or not?" You asked and decided he needed a little push. "Because I'm not going to wait forever."

He looked at you with an unreadable expression on his face. He took a step closer to you, placed his hands on the sides of your head and quickly leaned in, pressing his lips on yours.

Although you did encourage him to kiss you, you still found yourself feeling shocked by his fast actions. It took you a moment to return the kiss but when you did, you felt your knees beginning to give up on you. His hands moved down to your hips and your hands found their way to the back of his neck and you pulled him as close as possible. This was exactly what you had been waiting for, what you both had been waiting for.

As you pulled away, you rested your forehead against his, trying to calm your breathing. You opened your eyes too see him already looking back at you. "Eager, are we?" He asked with a grin and you slightly pushed him away. He chuckled and wrapped his arms around you, pulling you to his warm embrace. "To be honest, I was so scared of screwing it up," he sighed. "I just wanted it to be perfect."

You found yourself smiling as you lifted your gaze up to look at him. "All you had to do was exactly what you did just now. That was perfect."

He smiled back at you and leaned in once more but pulled back as he heard a scream behind them.

You both looked to the doorway of the kitchen to see Caden jumping up and down, clapping his hands together. "Caden?" You asked and pulled away from Bucky. "What's going on?" You asked with a smile as you walked up to your son.

"My wish came true!" He said and hugged your legs tightly.

"Did you get the big toy rocket ship you wished for?" You asked as you patted his hair.

He shook his head, still smiling widely. He looked to Bucky and then you. "You kissed!"

Bucky sent you a confused look which you returned. "Buddy," He started as he neared the two of you. "Your birthday wish was for me and your mommy to kiss?" He asked and Caden nodded, grabbing Bucky's metallic hand.

Bucky looked at you and sent you a wink which made you giggle. He pulled you to his side, threw his arm around your shoulders and kissed the side of your head. Caden ran out of the room, bragging about his birthday wish coming true.

"You know, you're a good kisser for someone who's 100 years old." You broke the comfortable silence you were having.

"I'm not 100!" Bucky exclaimed. "I'm 99." He muttered.

You laughed, "Sure, old man."

Bucky looked at you, placed a hand on his chest as if he was offended. You pushed his hand away and moved right in front of him so you could wrap your arms around his torso and rest your head on his chest.

"How are the rest of the team going to react?" You wondered out loud and lifted your head up enough to look at him.

Bucky let out a groan and dropped his head down to rest on yours. "I don't want to know." He said with a low chuckle.

"What if we don't tell them?" You asked with a raised eyebrow.

"I don't know if I can do that," Bucky pursed his lips. "I'd rather just show the whole world that you're mine."

You rolled your eyes and pushed him away. "You're no fun." You muttered as you walked out of the kitchen.

Bucky shook his head and followed you. He may or may not have checked out your behind very subtly as you walked over to the living room where all the guests were. "Hey, it was so nice having you all here tonight. Caden seems to love all the gifts you gave him." You said as you patted your son's head.

The guests left, not without the parents making some remarks about you and Bucky which you just ignored with a smile on your face and you said, "It was nice to have you over. We should get together more often," instead.

You closed the door and leaned against it. "Thank you for coming." You said to Bucky. "Without you, they wouldn't have stopped talking about my love life." You said with a laugh.

"My pleasure." Bucky replied. "Should we go to the tower now? The others are waiting for Caden."

You nodded, grabbing your keys before calling for Caden. "Please tell me Tony didn't finish that suit for Caden." You hopefully said.

Bucky didn't answer, instead he just avoided your gaze and you lifted your hand up to your forehead. "I'm actually going to kill him."

Caden ran towards you, put his shoes on (that he had just learned how to do) and grabbed Bucky's metal hand in his, then he took your right hand in his and pulled you out of your apartment.

"Do you need a lift?" You asked Bucky.

"No, I have a motorcycle."

"Do you have a helmet?"

"...No."

"Then you're coming with us." You said and unlocked your car. "You should really wear a helmet."

"But it ruins my hair!" Bucky whined.

You sent him a warning look and he got in the car, muttering, "You're such a mom." You nodded in approval and opened the door to the backseat, sat Caden down and fastened his seatbelt. You then moved over to the driver's seat, got in, turned the engine on and started driving.

"I'm going to have to come back for the motorcycle, alright? Steve will kill me if he realises I took it without telling him." Bucky pointed out.

You turned to look at him and smiled. "I know." You said and turned your attention back to the road. "Just remember to bring a helmet."