Relationship or Relationshit

She cheated three (3) times and each time he caught her and ask what he can do to fix the situation. Each time she said it was a mistake and that it wouldn't happen again. They do have children but they're all grown so him trying to make it work must be love. Of course she doesn't realize it or maybe she's an undercover nympho. She cheats a fourth (4th) time and he confronts her and her sex partner. It get physically, he moves out and files for divorce. He volunteer to give her the house so she doesn't contest the divorce. One year later she's lost the home, kids are upset at her, and the new man has moved on. Now she's rethinking her action and trying to sabotage his relationship. Personally I would have left after the second time because it's obvious it was a one way love affair. They were married for 23 years so I understand his hesitation but after so many unsuccessful attempts at fixing the relationshit. Should he now go back because she's learn the errors of her way and wants to recommit. Should there be a time frame on forgiveness