He broke up with her over the phone and said basically all that. He owes our marriage and me a chance, he made vows to me, he's ashamed he broke them, so on. He said from that point he wouldn't talk to her, so sending her a letter in top of that when he said his conversation was the end seems counterintuitive. I almost feel the letter has less impact than him sayoingnout of his mouth to her hears what his intentions are. The letter she could say I wrote and he copied or signed. There's wiggle room there for both of them. The phone call though? That's harder. Anything he says can't be taken back without damaging the trust he says they shared. He'd have to say he lied then or didn't mean it or whatever.
Well the phone call is done and over with. So right now, no letter is need. You brought up writing a letter to her and her husband and that was after he broke it off over the phone. I was addressing that. What a letter, if there is one, needs to look like, who writes it. And if it is written he signs it and the two of you both mail it together.
He could also tell her that you made him make that phone call. It happens all the time. They could very likely take the affair underground now. Telling her husband would have the added benefit of having the two of you keeping your eyes on them.
One reason for the letter is that it’s hard to end contact, with contact. A phone call is contact. He tells her that his affair was a terrible thing that he did to YOU? Did he tell her that he is committing to you and your children? This is an important aspect of the letter, that only talks about you and that he hurt you. That he never mentions anything about his feelings for her? Did he mention his feelings for her in the phone call? Did he tell her that he would miss her or anything like that?
Often, a cheater will say that they want to tell their affair partner in person. That’s a disaster waiting to happen. They go off somewhere to tell the affair partner, and it turns into a blubbering “l love you so much but need to end the affair” fest and often ends with sex and plans to take it underground.
I did send her the email already. It wasn't long and I didn't beg with her. I just laid out we were focusing on our marriage and if she intruded again that she was hurting children and risking public shaming as I'd bring every email and text and picture out for the whole world to see. And I said that for how he said what they had was special, the first sign of real resistance and he gave her up and resumed marital intimacy hours later. So at the very least she has questions about how special what they shared truly was since I'm sure she knows we weren't having sex that frequently.
Well it’s done. Except for telling her husband, ignore her in the future.
And please read the book I suggested.