Domestic Violence: Help

My question involves criminal law for the state of: Montana ok so here it goes I have been divorced from my ex husband 10 yrs now and honestly I thought I was over everything but turns out I am wrong. My ex is getting out of prison 10 yrs early for another pfma not related to me due to lack of something. But when he gets out one of our two daughters who is 12 now wants to live with him because she don't like mine and my new husbands rules. I don't feel this is a good thing because of his past but because I was brainwashed for lack of better excuse I never turned him for anything. Now its hard to get a complete answer because that would mean all the details which would take years to type. But my ex was physically abusive he hit, punched, threw things at me, pushed me out of a moving vehicle, he also would flick our then infant daughters in the head when they cried. He would put me down and make me feel as if I wasn't worth anything and then hours later love on me and say I was his everything, this man would take me into the mountains when I had done something he felt was wrong like go see my family without his ok he would punish me in the mountains (I am sorry for my next statement) he would punish me by raping me in my rear end. This sick man would send his friends over to have sex with me and if I didn't do as they wanted he threatened to kill me and the kids. He yelled at me and broke my stuff he accused me of cheating and he even attacked my dad once for getting in the middle. But in the end I never told a soul and now I pay the price. Please help me by telling me is it to late to stop him from getting my girls?

Domestic Violence: Help