"Tony?" You called as you stepped off the elevator. It wasn't a big deal, you dropping in once in awhile, but it had been a couple of weeks since your last mission and you wanted to see your boyfriend. Being a S.H.I.E.L.D agent meant a lot of things, but when you were assigned head of security (Happy wasn't too,well,  happy about it) for Tony Stark, you didn't imagine you'd fall in love with the guy.

You heard a clatter coming from the kitchen and you walked around the corner, catching sight of Bruce with a bagel in his mouth. His eyes widened and he dropped the bagel, much to your amusement.

"Hey, Bruce."
"H-hey, Y/N!" He stammered, reaching down to scramble for his food before popping back up with an abashed look on his face.
"You seen Tony?"

He opened his mouth a few times and you watched as his face grew dark.

"I tried to clean him up, Y/N, but it's been hell with you being gone. Really hard on the guy." He sighed.

"What are you saying?" You asked slowly.

"He-He kinda went back to his old partying ways,
Y/N. And I tried to stop him, honest, but...that didn't go too well."

You both whirled around at the sound of a loud crash coming from the lab.

"I'll get him." You muttered.

As you walked down the stairs that were mysteriously covered in broken glass, your heart dropped. You could hear the sound of feminine giggling and if it was what you thought it was, someone was about to get hurt. You stopped at the landing and your worst fear was immediately confirmed.

A curvy woman with long, black hair was pressed against Tony's side as he showed off his large selection of automobiles.

That you were secretly planning to slash every single tire of.

"This is amazing, Tony! When are you gonna take me out for a ride?" She asked in a high-pitched voice. You could picture your hands wrapped around her skinny little neck as she flipped her hair over her shoulder.

"We can go right now, if you want, cutie. I've got nothin' better to do." He replied, nuzzling her ear and making her squeal in delight.

You sighed and drew your gun from your holster, shooting off three rounds into the ceiling. Tony and the black haired woman jumped in fright as they turned to look for the source of the sound. His face paled and the woman widened her eyes as you trained the gun on them.

"Actually, I could think of a few things you could be doing. Like, explaining." You said casually.

Tony quickly withdrew his arm from the woman and pushed her away from him.
"It's not what it looks like, Y/N." He held up his hands.

"Right. So who do I shoot? You or you?"

A few moments of silence passed and the woman opened her mouth to say something, resulting in you firing off two more rounds in the wall near their heads.
She whimpered pathetically.

"If you could excuse us, ma'am, I have to talk to my boyfriend." You gestured to the exit and she scurried around you and up the stairs, her footsteps fading fast.

You rolled your eyes at Tony and holstered your gun as he slowly walked towards you.

"Not gonna shoot me, right?"
"I have half a mind to." You snapped. "What the hell is wrong with you? I thought I could trust you!"

"You can, babe! Look, I know that looked bad, but that was my-uh-cousin."

"You're so full of shit, Stark."

You began to storm off when he caught you by the arm and pulled you against him, trying hard not to flinch as you punched him in the shoulder.

"Y/N, I'm sorry! It's just that you were gone for so long and-"

"And you decide to go and get with any tramp that throws herself at you? Did you even stop to think about how I would feel? At all?" You yelled, yanking your arm out of his grasp.

"Y/N-"
"Obviously not." You steadied your breathing and tried to keep a level head, but it was hard. How many girls had he been with in the three weeks you were gone?

You knew Tony was a womanizer and it was something you were quite aware of being that it was your job to protect him. When he had asked you to go steady with him, you were a bit skeptical at first, but as time went on, you began to trust Tony. Which was something you regretted doing in the first place as you looked at the man you thought had loved you.

"I'm gonna head out. Sorry for interrupting you." You said sarcastically and turned on your heel to stride up the stairs, not bothering to look back.

If that's what he wanted, fine.
He didn't need you anymore, did he?
You were too angry to cry and much too angry to say anything to Bruce as he watched you stalk into the living room.

Bet he'll throw a party now that I'm gone, you thought bitterly as you got into the elevator and slammed your palm into the buttons.

You didn't think of how wrong you were as Tony Stark sighed sadly, watching the stairs to see if you'd come back down, even though he knew you wouldn't.

With all the pride and stubbornness between the two of you, it would be a miracle if the relationship could be fixed and it wasn't much of a surprise to the others when neither of you cried until a few days later.