I used to be game for threesomes. But now I think my BF is the one, and it doesn’t feel right. I can’t stand the thought of him having sex with someone else, even if I’m there. He says it’s unfair that I told him early on I was into it and now I’m veto-in
Your BF has a right to be disappointed and to tell you what he wants. But unfair? You have a right to say no, no matter what used to turn you on. He can’t demand a threesome. That said, you both need to put effort into keeping your long-term relationship hot. I bet you can think of some other new experience—let’s call it a consolation prize—that’s even hotter because you’ll both enjoy it.