Tony Stark:

Tony knew that he wanted a ring that represents the both of you so this worked, since you love the blue of his arcreacter and he loved hot shot red so it worked.

Bruce Banner:

Bruce knew that you didn't wear huge jewelry so he went for something simple but elegant and when he saw this he knew that it was the ring that he was going to propose to you with.

Bucky Barnes:

This is the ring that his dad proposed to his mom with so he knew that this was the ring that he wanted to propose to you with, he had it with him when he left for war and it's one of the only things Steve kept with him hoping go find him so he could give it to you himself.

Pietro Maximoff:

Pietro wanted to give you a ring that he knew you would say yes to so he asked your dad for help choosing and when they saw this ring they both knew that it would be perfect for you.

Loki Laufison/Odinson:

This ring was given to him by Frigga when she found out about you, she intended it to be used as an engagement ring, it was one of the only things he had left of his mother and so he decided that this was the ring he was proposing to you with.

Thor Odinson:

He wanted something elegant for you and he knew that he wanted something unique as well so when he saw this one he knew it was perfect for you, his one and only queen.

Natasha Romanoff:

Nat knew that she wanted it to represent her and you so she looked for a black and red somewhat simple one and she found this one and knew it was perfect.

Wanda Maximoff:

This was the ring that her dad proposed to her mom with, she knew that this would be the one to propose to you with, her mom and dad were very important to her and so are you so she knew that she wanted to give you this ring since she also saw a lot of similarities between her mom and you.

Peter Parker:

He wanted something that was simple but beautiful and represents why you two got together, so the blue and red hearts worked because you two met a few months after he became spiderman and the hearts represent his and yours.

Clint Barton:

He wanted your ring to represent him so you always had him with you and a reminder of how much he loves you.

Nick Fury:

He wanted something simple for you so that when you went out on missions it was hardly noticable, also you just don't wear huge jewelry so this worked for you.

Steve Rogers:

Steve found this in a lot of his parents stuff when they were still alive and since he was already madly in love with you and knew he was gonna marry you he knew this would be perfect for you.

Sam Wilson:

Sam knew that he was gonna propose with a simple ring so that it wouldn't get caught on things while you were working out or when you're in battle.