Child custody help

I along with my two small children are in a very emotionally abusive household with my husband(father) . He's gone to therapy just long enough for the therapist to see that he has a mood disorder and that he shows signs of narcissism, attention issues and shows traits of schizoid personality to sadistic personality features along with some alcohol abuse. I want to leave him so badly but I can't handle thinking he will have them alone for any period of time when child custody comes into play. What do I do?? Stay in an abusive marriage or get out and risk my children being hurt when he has them without me?? My only option really is to endure the pain for my children's sake. Any helpful information is greatly greatly appreciated.