You are the parent here and you are free to say what you want. But I will tell you this much, what you said it will not benefit you or a possible R in any way.
You made your son talk about it when he didn't want to in a parking lot? couldn't you wait until he absorbed some of this and then spoke about when he came back to your house? You just wanted him to know so bad right then and there. That was about you, buddy, not him. And to go into that much detail?! "your mom is having extra marital affairs" would have been quite enough. You told him she will cheat with anyone she can find? Then also bashed grandma and great grandma?! I mean come on, this poor kid, that is a lot at once with unnecessary information or him to know about his mother. And you basically bashed her rather than just giving a simple truth.
I hate to call people out like this, especially with such difficult circumstances. I was afraid it was going to go down like this. Your anger towards her is so apparent, and not unwarranted, but when you let that anger leak out in other ways, it isn't good for others.
Then you go on to ask Sandi if she might come back after it doesn't work out with the 25 year old? Your actions were that of a guy who does not want to reconcile ever, so why does that matter? Every hear the posters say "keep the road home paved and smooth?" I believe if you want any chance for reconciliation you need to do that. That doesn't mean I don't believe you should hide anything or cake eat. it just means you need to be truthful, yet careful and not vengeful.
What is done can't be undone. The breaking up of a family is never good, and yes, she chose to leave and cheat. You have every right to be angry with her about this. But I beg you going forward, please try your best to leave your anger out when trying to discuss this with your S. I went through the divorce of my parents when I was 17. My mother ripped apart my father to me. And my dad was/is an excellent dad. I didn't care about their marriage. My relationship was separate and I didn't want to know the nitty gritty stuff. Tell me the truth, fine, but putting me in the position of hearing the marital issues was not something I desired.
You don't need to find respect for her. but you should not put your son in a position where he feels like he needs to disrespect her either. Their R is independent of this. Let him decide for himself, without him knowing your personal feelings towards this.
