...Is there a nice way to tell him to stop doing things for me, because I don't want to feel obligated to him?
Like, if we go out with his friends, that's considered "normal," but if we go out with my friends, he thinks that I "owe" him. Same goes if he happens to buy me a gift that I didn't even ask for. It's frustrating.
Tell him flat out you don't owe him anything those are things couples normally do, sometimes you see something nice and think I should get this for my boyfriend and you get it for him. You don't have to buy him something just because he got you something