If did not trust the person I was living with with a gun, if I thought the only thing keeping me alive is their lack of access to a gun, I would leave so fast I would not even pack my belongings. In other words if anyone is comforted by a law keeping a spouse from owning a gun that comfort is an illusion. Woman who then stay because of this comfort and are killed anyway are killed because of this law right?
Also, the number of people killed because someone is denied self-defense tool by the is probably greater than those (if any) whor are alive because of the law.
Most such gun deaths are impulse sorts of things. But where there's a habit of violence and especially with alcohol, the step to adding a gun in the moment of anger is an easy one to take for many, many men.
So, yes, it would mean X% less deaths.
For a hypothetical law targeting only the people you describe, perhaps, perhaps not. For the law as written, no.
EXCELLENT POINT.
However, it's often extremely difficult to get the co-dependent spouses who've been even almost killed--hospitalized even--'tis often hard to get them to leave the guy. The relationships are sick from the git-go. YOU probably wouldn't have entered into that kind of relationship with that kind of person in the first place.
Many people--women in most cases in this topic area--see themselves as desperate for shreds of affection, comfort, support however twisted and transitory.