TALK, TALK, TALK, TALK!!!!!!!
I think you need to have a sit-down and a chat. I am going through a sex-thing also and the more you talk, the better.
It may be that he is uncomfy with the idea that his baby is in you, but it sure as hell has nothing to do with him not fancying you
For me sex was ok during pregnancy. It was uncomfy sometimes and other times it was great, mind you I did not have a very large tummy.
I don't think it's weird that you want to have sex while pg, just to feel how it feels If that was the case, then all of mankind is weird for trying anything other than the missionary/doggy-style

So after talking about his fears (so to speak), get your "weirdo" :P a$$ in some sexy black lace and sit him down and flirt your way into his pants!!

Goodluck!!