How do I get out?

My husband is verbally, mentally, and emotionally abusive.He’s been physically abusive twice now. He’s constantly back and forth between I love you and I hate you. He cheated on me during my whole pregnancy. He constantly puts me down and tells me how worthless I am. I love him but I love myself more. We have a 2 year old who absolutely adores him. I want to leave but I’m not sure how to go about doing such. He will fight me to keep the baby with him and give me partial custody. I work part time right now and barely make enough to pay our rent. I can’t afford to make a move right now and he doesn’t give me access to any of the funds other than what I myself earn. I’m at a loss here. What do I do?