You have not done your homework on domestic violence.
The sad fact is, most women in a violent relationship tend to want to stay in said relationship for many different reasons (fear, devotion, religious beliefs dealing with divorce etc etc). This will lead either to their eventual death, or a wake up call and their departure (with help from family, friends and support groups) from the relationship.
The better question is how do we get these battered, abused women out of the abusive relationships ASAP. There are many, many local, private and state resources dedicated to help these women. I do not know what more can be done, besides maybe early education I.E. teach women about abusive relationships in grade school on like we do with sex ed. And while we are at it, maybe educate young men on how they should treat their future spouses.
Dunno if it would work, but worth a try if it saves a life.