There is no way I can possibly read all of the responses to your original post, but I will say that I am having a similar experience. It isn't that my DH is being completely uninvolved the second time around but he has only been to one appt - the big sono to identify gender. He sometimes puts his hand on my stomach but I can count on one hand how often he has done this. He just isn't an overly affectionate man (unless it involves grabbing my butt - hehe.) In the ten years we have been together, he just doesn't like to discuss the hard things, kwim? He is the king of avoidance and perhaps this is your DH's way of not getting too close. As far as the role that IVF played in conception, I can't speak to that because I haven't been there.
Just keep trying to include him as much as you can. It's a hard time for everyone. And since you are older, is there a chance you might land on bedrest? If that is the case, then he will have to deal with a dose of reality. I am and while DH wasn't super interested in updates from my OB before, he sure is now, especially since he's waiting on me and the 3yo all the time.

I am blessed that he is so kind and patient but I also think he's getting a dose of karma.
And some men, they just aren't as verbal. And well, you are pregnant. Women are more sensitive in general, let alone when the pregnant hormones kick in. My 2nd pregnancy has been completely different from the first and it has certainly taken some effort for me to bite my tongue on more than one occasion because things bug me now that would have never bugged me before.
Good luck! I really do hope he comes around.