completely gone off sex!

I'm 30 weeks pregnant and since I was 5 months we have had sex, once or twice. I feel like it is a chore, I'm tired. I have a lot going on, and I don't like my body at moment.
He can't get enough, but it got to the point we are arguing about it now..
I feel so distance yet I ain't doing something just to make him happy. 
Help?!?