Abusers target those weaker than themselves specifically because they want to compensate for feelings of weakness and/or lack of control over their personal circumstances. They want to feel powerful and getting their asses handed to them by someone who is their physical match isn't going to accomplish that so they target women and/or children. Many abusers are smart enough to know that if they can break their intended targets spirit first, they will be able to convince them that they are unworthy of anyone better and they can control that person psychologically as well as physically. Abusers are mentally ill, which does not excuse their behavior. Most often abusers were at some point in their lives abused, which is what in most cases caused them to feel emasculated and weak. Male abuse victims often turn their hurt outward, finding ways to lash out, whereas female abuse victims most often turn their hurt inward, leading to such behaviors as self harm and dangerous lifestyle choices (including finding other abusive men to get involved with). This perpetuates the cycle of abuse.
While it might seem that what abusers need is a taste of their own medicine, beating the crap out of an abuser would only serve to make them feel more weak and emasculated which would drive them to seek to compensate for these feelings more desperately. What abusers really need is an exceptionally good shrink. Abuse victims need to understand that they are not at fault nor deserving of what is happening to them. That their life and well being is as precious as anyone else's and that they need to do whatever it takes to reclaim their dignity and self-worth and act in their own best interest. Abusers don't change without years of intense therapy, it just doesn't happen, regardless of how much they profess their love or claim to have turned over a new leaf. Abusers gradually escalate when they get what they want, and the abuse becomes worse and more frequent until eventually it becomes life threatening. Love is the highest form of respect, so if someone isn't respecting you, they damned sure don't love you.