What a nightmare, you poor thing. I just want to give you a big hug. I can't imagine what you are going through. One thing you must remember is you are blessed to be bringing your little girl into the world, you can do it on your own as can the other woman and without being cynical I'm guessing you will both have to. He sounds like a loser.
I don't blame you that you're thinking about the other woman, I would be. If it is possible try and share with your family and friends what is going on, I am sure they will be very supportive. You shouldn't have to deal with it, it's his problem.
I am speaking from experience in a way, not two people pregnant but a man that was noncommittal. He has gone and I am on my own, working full time but its the best thing I've ever done. My son is amazing; it's tough but worth it, so much less stress without FOB.
Take care of yourself and keep in touch. X
Ps I wouldn't have him at the birth, although I let mine.