Single mom, custody, and divorce advice?

Jessica

So I recently found out that my husband has been sleeping with numerous women for the 3 years we have been married. I am devastated and even more broken since I am 23 weeks pregnant. I have started the divorce paperwork but He is being incredibly mean and is repeatedly saying he is going to get 50% custody plus fight for everything we own. I don't work as our plan was for me to be a stay at home mom. I understand I will have to work full time after the baby is born but in the meantime I have to move in with family. It's so horrible because he is a sex addict, lier, and suffers from PTSD since he is a firefighter. I don't feel comfortable with him watching our son alone after he is born. Plus the thought of giving away my son half the time tears me to pieces... every time I feel him kick I cry because the thought that I can't be with him everyday after he is born terrifies me. Any advice for a single mom? How to cope with seeing your first child 50% of the time? I just don't know how to handle all of this:(