I think you might want to back off on the family dinners. You are beginning to chase him again. You might consider pulling back and having him chase you. Make sure the things that caused him to leave get addressed.
Keep getting a life and becoming the strong new you.
If he's serious about breaking it off he'll write her an email that he shows you telling her never to call, email, text message him again.
You can ask him to do this only when he is sure and ready that he wants to break it off.
The more you push him to break it off with her, the more he'll be drawn to her. His endorphins haven't worn off yet. He still has deep emotional grooves with her.
Don't give her any speeches at all. He will still defend her. The more you attack her, the more he'll want to defend her. Let her hang herself. Don't involve yourself in it. She's not worth it.
You are doing well, but you still have a long way till your out of the woods.
