Who's the bad guy?

My boyfriend and I had made a bet, and I said if he won id do something him and vice versa. Well he won and what he wanted was to do anal with me. And I didn't want to do that so I said no... He's not trying to force me to or anything but he is upset because I said I would do whatever for him but I said no. I feel bad for saying no but I don't wanna do it. So he's upset about it because we had a deal and I said no