Men who emotionally/physically abuse their partners are most likely also manipulative liars and seem like they have a split personality. They may act different in private.

Blaming the women in this situation is not always fair. They are not the evil abusive person in the situation.

If they were genuinely in love with the guy at some point for whatever reason, sometimes it is very difficult to leave, even though leaving is the obvious choice to people viewing the situation from the outside. This could be for various reasons. It could be because they are used to the routine and cannot break the cycle of abuse, they are extremely afraid of being alone, they are financially dependant, or they feel it is best for their children.

I can't speak from experience, as I have never liked "bad" guys. I like compassionate and romantic men.