OP, I don't want to get on the same cart as the others and say 'leave him' because I don't think you can possibly throw away your marriage on what's happening now. That said, this isn't a 'get out' clause for you H because he is acting selfishly and being very, very hurtful. F
rom my experience, giving a man an extremely wide berth and leaving him to stew in his own consciousness always helps. I don't know what the time scale on this whole issue is, but if I were you, I'd carry on as you are, that is - solo parentis - and take this time to gather your strength (although it sounds to me like you are made of pure heart and iron - your DC are lucky to have you) . That way, your H can have the time to try and figure out how he has hurt and failed you so badly. Somewhere, somewhere inside that screwed up thinking of his, is the man that you love and married.
It is still completely plausible that he's thinking in pure biological terms and before everyone else gets indignant and defensive about this, it IS possible. We don't know this man at all, how he thinks and how he works - it IS possible that he has not bonded, of course it is. The OP's closed-case reaction to this (i.e. there is NO question of a termination and that's the end of it) is perhaps only making him dig his heels in further. If I were you OP, I'd write it down and post it in an email or a letter. Terminating HIS child, HIS flesh and blood, terminating a now living and moving baby will be like killing a part of you both. And most certainly killing a part of your marriage that will be undoubtedly, beyond repair.
I know a lot of you will disagree with this - acting like this will be a deal breaker for lots of MN'ers, but OP loves this man and I can't see how you can right off a marriage so quickly without digging a bit deeper and trying to find a reason for his thinking. If I've not helped at all with this post OP, please ignore it, but either way please know that you were one of my first thoughts as I woke this morning. I really, really hope that everything works out for you.