Need advice

Hi! Been married for 12 years now. When me and the hubby first met he was awesome. We fell head over hills with each other and got married just after 2 months of dating. He was perfect and then he changed. He started to be mean and lie constantly. I have caught him in so many lies I could be here all day. I have a son from a previous relationship and he was 7 when we got married. He started just ragging on him about everything. Bitch bitch and more bitching. Hollering and fussing and cussing. My son used to adore and love him but now he hates him. Fast forward 6 years and we had our daughter. He does her the same way he used to do my son. I tell him all the time she is going to hate you like our son does. He won't stop and he doesn't listen to anything I say. He has broken my heart so many times. And so many times he promised he would change and try harder and he never does. He hits walls, yells, cusses, lies, throws tantrums like a little kid. He has broken the tablet I got for him, broken his cell phone, broke the mirror of our car, put a hole in the dash of our car, he ripped our marriage license up, he has put multiple holes in the walls etc etc etc. I am at the last of my rope. I have no job, no money just nothing. I can move in with my parents but that don't solve the no money thing. I want to stay with him, but he has git to have some type of mental disorder. He has been through a lot in his life but it is no excuse to be an ass to someone who has been through it all with him. I only have a 2 year associate degree in general studies and haven't worked in 12 years what kind of job could I get with that to support my kids? I want to separate from him for a while to see if he cares enough to want his family back. I just don't know what to do....