there is a complex psychology involved in an abusive or psychopathic relationship. The abuser typically seeks out a woman that has a strong maternal instinct and corrupts it. As bad as it is for a victim's children, it is her instinct to protect that keeps her coming back.
My grandmother had a strong maternal instinct and she carried an ice pick. My mother carried a .38 - no abuse while I was growing up.
Some people are just plain stupid. At least that's always been my view. I may be cold hearted but I have no sympathy for them, and if there are kids in the mix then the mothers are just as bad as the abusive man because they are forcing there children to grow up in that environment.