Some form of social service intervention for the whole family would be far better than arresting one person.
After all, somebody abusing someone else likely doesn't handle stress and anger appropriately: nobody's life gets easier and more manageable after being arrested.
So longer prison sentences for domestic abusers then? Put them away long enough so the other party is forced to start their own life and no longer be in a situation where they are dependent on the abuser and thus unable to leave.
Long prison sentences might help a few cases, but not most, because most won't be convicted in the first place.
It's important to help the victim directly, not just focus on removing the perpetrator, because the latter is likely never to happen.
Note also that because the situation is often so unclear to the police, sometimes both people involved to be arrested, or the victim is arrested and the perpetrator goes free. The latter is especially common when the victim is male.
So no, police arriving and arresting who they think is the attacker isn't necessarily desirable.