Very similar case happened to one of my co-workers. He married a woman who was a narcisist/compulsive liar/alcoholic who was verbally and physically abusive towards him. She made up all sorts of crap about him when they finally got a divorce, and she got partial custody when anyone who knew her could tell you she was a crazy bitch. Fortunately, after a couple years of legal battles, he's finally gotten full custody(he built up a stack of evidence and witnesses to attest to this woman's pathetic excuse for parenting).
Thanks for the support. You see, the presumption was that she should have custody, and the man had to move heaven and earth to prove that she shouldn't. If the sexes were reversed, would she have had to go to such lengths to deny custody to the father? I think we know the answer to that.
I know another case of a divorced mother who is a total psycho. She beats her kids and they're suffering all kinds of developmental problems. The father wants custody of the kids, and they are begging to live with him. At the time of the divorce, the kids were young, and the father was told, "In about ten years, somebody will listen to the kids, and maybe award you custody. Until then, you're out of luck."
Now it's probably too late for the kids to recover from their years with this woman, even if the father gets custody immediately.
Feminism has fought very hard to put and keep this anti-father system in place.