A fear I don't think will ever go away

My exhusband was abusive, and he's also unreasonable, a drug user and maybe, well totally, is crazy. He told me he was going to kill me during the start of our divorce and he went to jail for the threat. It's been five years, but I cannot get over the fear that he will really come kill me. When he is in jail (often) I feel safe. When he isn't, I feel fear and paranoia. He's in jail now, but during this last stint in jail, my new husband adopted my exhusband's son. He wasn't able to object, because he got thrown in the pokey 2 days before the hearing. I'm so scared that when he gets out soon, he's going to kill me this time. Out of revenge or something. I know it is probably all physiological, like a fear that will never die, until he does, but it's just a feeling I live with. I'm so ready for him to croak, or go to prison for ten years. Sigh. Thank you for reading. Any comments are welcome :)