I don’t want sex with my boyfriend..?

So my boyfriend and I have been together a few months but have known each other a lot longer. I’ve previously been with a few other people, so we both know that I’m into sex and not Asexual or anything.

It’s just him..?

He’s a lovely guy, and I enjoy spending time with him.

But we’ve tried sex a few times and I just.. I don’t like it with him. It’s not that it’s particularly bad or anything, it’s just the thought and the actual doing really puts me off. I dread it!

I don’t know what to do. I feel awful, because he’s really enjoying it and I’m not. The first time we tried lasted 2 hours and neither of us managed to finish. I had an anxiety attack and he kept pushing for me to finish him off, even when I said I wanted to stop. Now any time we’re alone he’s pushing for sex, and I’m pushing back to say no. I don’t know what to do. :///