Jilted by the same guy twenty years or so later

11 months ago, an old boyfriend came back into my life. We had dated over 20 years ago and had a bad breakup way back when. He had broke it off on me. After a week, he told me he still loved me and had never loved anyone as much as me. He would tell me that we were soulmates and always meant to be together. I was miserable in my marriage, but stayed in it because of my children and he knew this. He also knew how close I was with my kids. Soon he started putting demands on me. He lived 1000 miles away, and told me I'd have to leave my children to be with him. My family found out about him and soon everyone stopped talking to me. I lost the relationship I had with my daughter because she no longer trusted me. Two weeks ago, he broke it off again. He didn't lose anything from this. He pursued a married woman and helped to destroy her life and then walked away. I'm left trying to pick up the pieces and restoring relationships. I'm still in my marriage with a guy I have no feelings for, just for the sake of my kids. I know this other guy was bad news, but it is killing me that he could tell me a few weeks ago he loved me, and a day or two later he didn't. I'm not sure what to do.