It's hard to make this question grounded in data, but here's an anecdote I do think is accurate.
My grandfather was a horrific man. He died of complications due to alcoholism before I was born. That said, I've heard a lot about just what he was like, including from people outside the family. I've also seen 16mm film footage of him at family holidays, and it's shockingly clear every single other person in the room is straight up terrified of his potential temper. I'm not exaggerating on this point. I think he must have had something going very, very, wrong inside that skull.
My grandmother, who otherwise was a fiercely independent woman, stayed with him despite the abuse. My Dad, hitchhiked to Mexico one summer to escape him, but otherwise still tried to be the good son.
Why? Why not just divorce/disown the asshole?
The norms against that half a century ago were so much stronger. I do think that's an important shift that's happened recently. There's still plenty of people that stay in a bad situation due to loyalty, but the stigma, in the sense of victim blaming, has definitely eroded within my lifetime.
This is a very good thing in my book, even if it looks like a decay of society to some idiots.