The age thing may really have a lot to do with it! My husband is 32 and he is all over me and wants it all the time!!! Just be sure to let him know how you feel about it!
Get sexy, do your hair real nice, put something on that you know he'll like and trust me daddy will be all over you.
Maybe it's age? I hear a lot of younger women with this same problem. We waited until we're over 30 and he hasn't been able to keep his hands off of me since I got over morning sickness. Try suggesting a position where he's not leaning against your stomach, like on your side from behind. I'm sorry you feel like he's not attracted to you right now. Let him know it's guaranteed birth control and that women are notoriously wet and horny during pregnancy. Not to be crass, but if it turns him on to know you're really into it, it might help.
Your lucky ive gained 50lbs and im only 26 weeks and most went to my butt... maybe he is scared to hurt you or the baby try talking about it more