What's wrong with me?

So every time my boyfriend and I have sex or do the other stuff I can't cum. Like I can't. It feels good but at the same time i feel weird. So I fake moan, yes there Is times where it's a real moan. But he can never get me to cum. And even when its by myself I've tried everything. I literally CAN'T cum, (I've tried clit, penetration, all of it). What's wrong with me