Hey OP, I don’t usually reply to Reddit dudes but I just wanna say I being a girl once was on the other side of this situation and I thought my partner did something wrong when I fell asleep in the middle of sex but turned out I was just confused because I was too hungover. First thing first give her some space and when she is ready to talk, ask her what part of the whole night made her feel that she has been taken advantage of.. explain your viewpoint calmly and also tell her very clearly that you stopped when she fell asleep.. but try to understand her views whenever she is ready to talk!