Steve Rogers
When the two of you train Steve is incredible careful, he is so scared that he will really hurt you that he goes easy on you because of it. You have proven time and time again that you are faster at dodging and ducking from punches but he still worries for your safety. You love the time together even if he goes easy on you because it's more time you know he's safe.
Tony Stark
Since you do some boxing in your spare time you offered to help Tony with his hand to hand combat. You whipped his butt a few times before he really got the hang of how to move and dodge, even landing a few blows, which left bruises the next day mind you. You love being able to help him, spend time with him; and, on occasion, whip his butt.
Bruce Banner
You know Bruce doesn't need to 'train' because he basically turns into a seven plus foot monster that is almost all muscle but you need the exercise. You managed to start taking a more walk with Steve, well he ran you walked but it was company none-the-less. Bruce ended up getting jealous and started to do this morning ritual with you, making you really happy that he wanted to come even if it was because of jealousy.
Thor Odinson
After being attacked so brutally by Loki, Thor decided it was best to teach you at least a little bit of combat skills. You weren't too sure that you would like it much but you ended up really enjoying yourself and your new found potential. You spent a few hours a week learning tricks and tips from all of the Avengers but really loving the time you spent with Thor the most. Knowing this the Avengers secretly made excuses so you two would 'have' to train together, neither of you questioned them because you enjoyed the time with one another.
Loki Laufeyson
Loki was not very good with physical combat of any type, he was a long range, speak through problems kind of man and you were the exact opposite. In all honesty, you reminded him of his brother in that aspect but he loved you all the same for it and even agreed to your sparring 'contest'. The contests soon turned into training sessions for him and he became more and more interested in the teachings. You loved this time together, loved teaching him things he didn't know seeing as he was the 'I'm better than you' type and this was something you were always better at than he was.
Clint Barton
For the longest time the two of you actually never trained together because you would always end up just talking and sitting around. You would always train with Steve when it came to the physical aspects of your job but when it came to your specialty; sniping, you did that alone. You would always do your sniping alone in the target rooms of the Helicarrier until one of those times Clint was doing the same with his bow and it became a competition. Now, this is what you look forward to on training days.
James "Bucky" Barnes
You had trained together before and it didn't exactly go well for you, ending up with broken ribs but you didn't really care because it was time with Bucky that meant more to you. He on the other hand was an emotional wreck from the incident that took you a few weeks to calm him down from. Now, he is so incredibly careful training with you that sometimes you have to bring the Winter Soldier out in him just to get him to actually do some work. You know how dangerous that it but you also know that, deep down, he would never kill you and if he ever gets out of hand one kiss can bring him back to you.