My little sister went through a whole string of losers. I mean drug dealer who hit her in one case.
We found out that he hit her, and they were broken up over it. But she'd have gone back. She was already pining. My brother and I went to his work, and made it clear that if we ever heard his focking name again, he would deeply regret it. He ended up beating up his grandmother and being shot and killed by his grandfather.
Anyway, eventually she pulled her head out of her ass. She invited a guy to the house for a holiday function, and said she though this was the one. I went and met him with low hopes.
Turned out to be a great guy and perfect for her. I knew he was a keeper when he said something to the effect of, "I want to punch your real dad in the face for how he treats her."
Anyway, my point is, you just gotta ride it out. Hope that she doesn't make semi permanent mistakes first (marriage or baby.)
You kind of contradicted yourself above. First you say you and your brother had to threaten the first Dbag or she would have gone back to him. Then later you say he has to ride it out. Seems like you didn't ride it out when you thought she had picked a loser. Just sayin'.