I'm not "big" on The Bible, myself; but the way I see it is this: People who want to follow The Ten Commandments often say that things like drinking and smoking are a "sin" because they can harm the body (and other people as well). From what I understand, that falls under "Thou shalt not kill."
Reason would tell me that a woman who remains where she is being harmed could be said to be going against the "Thou shalt not kill" commandment; and even empowering her abusive husband in going against that commandment as well.
Jesus or no Jesus, I say it's more of a sin to stay than to leave and divorce. And that's not even saying anything about the fact that the abusive husband broke his marriage vow to love, honor, and cherish his wife.