QofQ hello [whispers congrats ]
When we found out we were expecting OUR #3, DH was physically sick with shock and would certainly not have stood in my way if I and mentioned termination (which I did not and could not; same reasons as yours). He took a good while (a few weeks?) to get used to the idea, although knew from the outset that we (or I if necessary altho this aspect was never voiced) were going to have this baby.
The baby when born was (IS!) Alex.. who was far more than either of us bargained for as you know (well would if I wasn't posting under a daft name.. it's SleepyJess) and he remains the 'highest maintenance child' I have ever personally come across.. and yet DH and DS2 (now 6) have a very very close relationship, always have, and he once said, perhaps not in so many words (because he isn't given to flowery statements!) that for all the things he's never achieved in his life, he thinks maybe he was born to be Alex's dad...
Hope that inspires you a little. Your DH has had no time at all to get used to the shock (n male terms!.. women get used to this much quicker; think it's biological). How he feels in a few days and then a few weeks is likely to be much different to how he is feeling now.. and from a practical point of view, you must just sit it out because you know.. and we know , that the termination option, in this particular case, just aint gonna happen.
Thinking of you..
SJ x And PS, just as a footnote, DH might want to do that vasectomy-thing quite quickly now! My DH was 'getting his head around booking up' after DD was born.. then suddenly, when she was 10 months old, I was pg again .. and he got his head around it ever so quickly all of a sudden!!!