When a woman's batterer is finally arrested, she is often the first to plead with authorities to let him go. He is her provider, perhaps the father of her children; she "loves" him. More to the point: she is now really afraid that he will kill her because his abuse has been publicly exposed and he has been arrested for it.
When a woman turns to the law — which is there to protect her — she may be endangering herself even further. As powerful as the law may be, criminals do not obey it and police officers cannot be everywhere and at all times. When the law is not looking, the further outraged abuser will exact vengeance. He will kill the woman who turned to the law, who publicly shamed her husband and family.
This is what Muzzammil ("Mo") Hassan did in Buffalo when his wife Aasiya finally got an order of protection against his savage beatings and verbal and psychological abuse. He beheaded her. This is what husband-batterers of every ethnicity tend to do — not behead, but murder battered wives when they leave or turn to the law. This is one reason that so many battered women stay.