Do we have a case?

I have recently married a wonderful man who has children. We have joint custody of those children but to our dismay, they live with their mother most of the time. Their mother despite her best acting is being verbally abused.(we have a police report on it) Shes miserable, we know this for a fact. What worries me is that they behave this ways infront of the children. My children hate going to their mothers house because of the man she married, he runs that household like a prison controlling everything they do. We have lots of documentation on certain events that have occurred over there. But my question is this, Is verbal abuse a good enough reason to go for custody? Im worried about how it will affect my children down the road. if there is an attorney in the house I would heartily appreciate some opinions.