It sounds like he has already mentally "chosen himself," but ok. Release him from his self-imposed obligation to buy you a house. It's weighing on him in a way that's not helpful. (Besides, if you stay together, you'll need somewhere to live anyway, and it will just make sense) Tell him you'd rather be a family together under a bridge. Tell him you want him to be happy even if things don't look the way you'd originally planned or expected. Tell him relationships can suffer and end OR can suffer and come out stronger. The future is not predetermined. I recommend you start/keep working. You'll be in a better position financially and have more options if his or your feelings change in the coming months. If you believe it's right, fight for your baby(!), and don't let his desire to keep you at home (short term goal) detract from keeping your relationship and family together (long term goal).
It’s not up to him what his obligation to his children will be. Let the law decide. If he wants to do more for you then fair enough.
Keep the baby. The baby will be your blessing you will see after you give birth! A lot of ppl that I know who keeps their babies now could say it’s such blessing. It’s not fair kill a baby because our fault.
Definitely a touchy subject. If it wasn’t in the plan there should have been more precautions taken because now in a way it unfair to you both in different ways. He is taking a more logical stance as most men would , it could very well be a set up for struggle & resent that would effect your relationship greatly and I think it’s admirable that he feels obligated to buy you a house along with doing his part with the children ( not that it’s optional) but most men are more difficult. You as a woman though have emotions and after your appointment developing an attachment is normal plan or not. However final decision has to be a joint thing in order to move forward together. Definitely more to think about and talk about amongst each other because family is important as well as staying true to yourself. I pray you guys can compromise, see each others sides and find a way to move forward.