I can't have an . Why? And what should I do about it?

Hopefully this isn't too inappropriate for this site. Anyway, so with my current boyfriend is amazing so far. He is so creative, sensual, and attentive. But for some reason, I can't climax even after close to 2 hours of . He is so determined to make me have an and it seems as though he's doing all the right things, but I can't get there and I have no idea why. I do not have problems with s when I masturbate so it's not that I am incapable.