Hey there,
Take all responses with a grain of salt because none of us know you guys and I'm guessing most likely none of us are certified marital counselors BUT - it has been my own experience that what you are going through is TOTALLY normal.
Not only is it due to crazy hormones, but also to being huge and uncomfortable, and exhausted, and to be frank with you - possibly a little tiny bit because of him; meaning that he may be a little freaked out that this is actually happening. Men are so visual, and during the first stages of pregnancy, you don't show much - but later, at the end, when you are clearly with child.... it is intimidating to them. My husband gets the same way... and its NOT because he isn't in love with you or because he thinks you're ugly - its a combination of uneasiness about the baby's presence, the fact that he is really going to be a father and that not only is he actually going to be a dad but its going to happen SOON. You've had 9 months to feel this pregnancy - he's only had a few solid weeks of realization.
When I'm feeling upset (I am 30 weeks along but we've done this a few times hhaha) ....but when I'm feeling disconnected and upset, I tell him how I' feeling and that I need some time alone with him. We usually put a movie on and cuddle before bed, making sure to love on each other and be very affectionate. This helps me a lot. Sex is extremely uncomfortable for me right now, this baby is breeched and not to mention large... we're already at 4 lbs and we have 2 1/2 months to go!
Try showering or taking a hot bath together. Try more affection and alone time, even if you aren't having sex. If you can... (and I know its difficult, and there will be nights that you just won't be able to).... but if and when you can, try to meet his needs. Obviously, you don't have to do anything you don't want to, and you shouldn't force yourself to - but on the evenings when you're not feeling sick or exhausted... give it a shot.
Intimacy is one of the super glues of marriage.
Hang in there!!