Serious marital issues

Jaclyn • I`m 28 and my husband and I have an 18 month old little boy. We have decided to try to expand our family.
I'm 37 weeks and 4 days along in my second pregnancy (our second child). I really thought by having another baby it would help for my husband to get his act together. He wasn't a part of our 2 year olds first year so I wanted to give him a chance to experience this. So he stays out all night, pretty much every night. He blames everything on me. Constantly saying all of our problems are my fault. I'm so stressed and exhausted. He doesn't help me at all and he just comes home when it's convenient for him. Our son loves his daddy n it hurts me so bad that he only sees him for a few minutes a day. So I just really don't know what to do. Do I hang out and hope for a change or leave?