This has made me chuckle (sorry OP)
Don't feel guilty; it's his issues, not yours. I suspect that rather than genuinely being disappointed, that this is a manifestation of his impending paternity becoming more real, so he is reacting in a an odd (and for you horrible) way. Give hime some time, and as others have said take hime to ante-natal classes for support. If it were me, I would just ignore him, and concentrate on yourself and the baby; he'll get his shit together soon (he's going to have no choice ;) )
Incidentally, my DH was totally convinced we were having a girl. DS wanted a boy. They kept bickering (my DS is 11), and Dh had the audacity to say that it was definitely a girl because I had 'gone wide' :O (I have actually gained very little shape). I am expecting a boy, DH sulked for a few minutes, more I suspect because he was wrong, and DS had a weeks hilarity calling me 'wide load', until pregnancy hormones got the better of me and I burst into tears. He was really upset that he had upset me (not that much actually,just hormonal), DH told him off for calling me that which made him worse, and I was annoyed as it was ultimately DH's comment that was the cause. In short, I kind of wish the pair of them had 'got their shit together' and kept their mouth shut. Men!!!
FFS
Seriously OP, have some
and
and wait for his male brain to catch up (might take a while... :) ), and be grateful you are having a girl who will hopefully never act like this xxx 