It sounds like your DH is just worried about hurting the baby (or you), I'm sure his reluctance has absolutely nothing to with him thinking you are not sexy. Maybe just start out with lots of foreplay, and I'm sure he won't be able to resist DTD, LOL.

The last couple of times my DH and I have DTD (I am 28 weeks) I have experienced extremely painful and uncomfortable braxton hicks contractions, so DH (and I) have decided to put a ban on DTD until we actually want the baby to come, LOL. It's just too painful and they last for a couple hours, so I end up getting no sleep. We have decided to just stick to doing "other things" till the baby is due.