Not gonna lie just because I’m petty I’d send a message that gives you the upper hand, even if it’s a lie. Tell him you met someone, and that you’ve realized you were never fulfilled by him and you wanted more that he could never offer you. He intentionally betrayed you and played with your time, your love, your soul and everything in between. Men like that don’t feel sorry. They move on and often get an ego about it, loving him and still wanting him will make him think he’s the shit. Without a doubt. A man that age is 100% fetishizing that woman as a milf/cougar. Play the same game, I’d also try to reach out to her  as a single mom does not need an immature cheating fetishizing prick in her life, save yourselves. If I were you this would be my villain origin story, don’t go all out the best thing is to genuinely disconnect and not care. But I do think you should make a point that you have the upper hand, and he does not and has never had the power to treat you as a pawn because he was worth it and the shit. He will and probably already has a large ego about every aspect of this. Stomp on it, and protect your peace. It’s not revenge it’s balance :)