How Do I Leave Him?

Compassion and wisdom please. He is not physically abusive, he is verbally abusive and sometimes makes advances like he's "about" to hurt me.

We've been together 2 years. We have a 7 month old son and I'm 6 months pregnant with our daughter. I'm due the end of December and I'm high-risk. He's the only one with a job, he makes the money. I have maybe $50 to my name. We have $150 in a joint savings account together. We live with his parents. He won't let me have anything in my name. My car, car insurance, phone, and phone bill are all in his and his parents' name. The only thing in my name is mine and my son's Medicaid and his WIC. I have a place to go (my dad's house) and I'm always welcome there, but I have a cat. This sounds so ridiculous to some people but I CAN'T leave my cat behind. It has me in tears just thinking about it. She is the only thing that keeps me sane and we're so attached. She would be a wreck if I abandoned her. I would be too! My dad hates cats but he would let it slide if I brought her. The only problem is how to load her and the baby up in the car without anyone knowing. Yeah i could try to do it at night but we have a dog here too and he would make noise if he saw me going back and forth outside loading up my car. Plus i dont want to be charged with stealing a car since technically it's his family's. My dad's house is also noisy because my 8 and 10 year old nephews are always there after school. They'd harass my cat and my son would never get any sleep. I dont have a facebook or any social media, he wont let me. He has access to the phone bill account so he screens all of my texts and calls. Please. What do I do? I'm begging for answers. I dont want to go to a shelter, not when my dad is an available source. I can't leave during the day because my fiancé and his parents would prevent me from taking the baby. His mother has literally held him away from me when I've tried to leave before.

Please somebody answer ASAP. I want this done within the next week or so.