1) Abusers are often very smart, very talented, very convincing. They might seem like wonderful men to family and friends. They might seem very honestly apologetic after the fact. And many of us took Psych 101. We know that we respond very well to inconsistent systems of reward and punishment. We love gambling. We prefer stocks to bonds.
Yet in the present case we have a man who, though he beats his wife, is often very charismatic to the rest of the world, and perhaps to his kids. And even if he beats his kids as well, it is known that intermittent affection can be a stronger binding agent than consistent affection. We also have a man who has demonstrated his power over another human being through brutality.
2) Women who are abused by their husbands have often been abused before or grew up in abusive households. They might feel like this sort of situation is normal. They might not feel like they deserve any better. They might not know how to get out.
3) Women make less money than men and are often tied to abusive husbands by fear for their lives or of losing custody of their children. And have you ever seen the way shelters work for battered women and their children? Would you take your children out of their suburban houses and schools and put them into that situation? It's never as easy as it might seem.
4) Women are not believed when they claim that they've been raped or abused. And women are blamed for rape and abuse. Still. Today. After all this time. Men rape. Men batter. Men are to blame.
Many years ago I dated a guy who is probably now a classic wife beater. He was smart and popular. He made me feel like I was the luckiest girl in the world to go out with him. Once we started dating, he'd say bad things to me about my friends. He'd tell my friends that I said bad things about them. He got angry when I'd make plans without him. Gradually, he isolated me from all of my friends, making me feel special and loved all the while. He missed me when we were apart. He loved me so much that he was jealous when I spent time with other friends. He used to tell me how much he loved me. He used to tell me how he had a bad temper. He used to tell me that if he ever got really angry, I should leave the room immediately because he couldn't control his temper and he didn't want to hurt me.
Get it? It was my responsibility to keep from getting myself hurt - by him. Lexus (see above) probably sees the reason in that flawed logic; I don't. I'm smart, I've watched the after school specials, I know better - and I still fell for this guy.
I did leave, I didn't get hurt, and I managed to rebuild many friendships that had been damaged. I was lucky - in part because this guy was still learning his craft. Many women aren't so lucky.