I was a single parent from the start too. My mother was my birthing partner.
You have a very difficult decision to make about whether you have the baby or not, and if I were you, I'd tell your husband to leave the house immediately to give you some head space. Make your decision based solely on what's best for you, not him.
In my case, when my baby was born I found it made me into a very different person. Motherhood changed every aspect of my being and I was in awe of how it changed my perspectives of the world. The love I felt for my daughter was simply so enormous, and so different from any other love, that it got me through the very hard early years (she didn't sleep very well and I also lost my mum when she was about a year old). Being a single parent is hard, but it is also wonderfully rewarding. We have a very close bond with each other, probably in a different way to if she'd been raised in a two parent family.
She's at University now, but though out her childhood we went abroad regularly from when she was three months old, including a trip to Australia when she was about six.The sense of freedom, and all the practicalities are considerably different obviously, but I found that it was fairly easy to make the necessary adjustments because I had changed so much as a person. That's just what becoming a parent does to most of us, I suppose, whether you're a single parent or not.
Finances are very important as a single parent, and life is easier the more money and assets and security you have. My daughter's father has never contributed anything, but my advice to you would be to take your husband's offer of having the house (tie up the legalities asap before he changes his mind) and get as good a maintenance settlement as you can going forward. You and your child (if you go ahead ) deserve it for the appalling situation he has landed you in.
If he's been so unhappy in the relationship for so long, why on earth didn't he tell you before ttc? It's beyond cruel to behave as he has at this time. I think his behaviour sounds rather too calculating to be a sudden and genuine mh crisis . He sounds incredibly immature and selfish and I also would suspect there is another woman in the background. I'm a cynic, but would certainly reserve judgement on whether he will ever make a good father.
Good luck to you whatever you decide to do. If you do decide to be a single parent, seek out other single parents in real life - there's plenty around, and you will find it an enormous support.