how am I supposed to do this?!?

long...i really need advice though!!! my daughter's dad and I separated 3 years ago. he started dated someone else who to say the least is Looney tunes crazy!!! This woman is obsessed with me because how he feels for me. She got pregnant to trap him. it didn't work. they broke up. he and I have always lived eachother. we are drawn like magnets to eachother. we started hooking back up. I was on the pill, one tube, one ovary, and now 16 weeks pregnant. I have 3 kids and work in healthcare. my schedule is crazy! I barely make ends meet. this other woman is constantly threatening to take his baby with her from him. says I am not allowed to be around his kid?!?! He is stuck in a contract with his 2 bedroom condo. he also hasn't told her we are having a baby. I'm financially stressed and emotionally stressed. he is so back and forth with me because he's so afraid of her. anytime I help him he's happy but when I disagree with him then it's a huge fight and he says he can't go back to that life with me. I have daily panic attacks and have not bonded with the child I'm carrying. I can't do it alone but he says he can't move in to help because of his house. he let's this woman call all the shots and its ruining us completely. I can not live alone and afford it. I can't be a single mom to 4 kids!!! I feel like I'm chasing this man, trying to make my struggling family together, and that my baby has to be this big secret from this other. he says when he tells her then she won't let him see his child. the expections are totally unreasonable! I am so lost on what to do about he and I. I am strssing about how the hell I'm going to raise with no help in any way. I am stressed to the point i have day panic attacks my other children are tired of me being grouchy. I wish it were as simple as just relaxing. wwyd???