Given the OP posted on the 6th of March I don’t imagine she’ll be back. Still.
I had an affair. Do I regret it? Absolutely. But it was the catalyst which ended an emotionally abusive marriage. But for some reason whenever someone mentions an affair it seems to obliterate everything that went before it. It doesn’t matter what the other party has done, the affair is the ultimate betrayal and the person who cheated is the only reason for the end of the marriage. At least that’s how people seem to see it.
My ex told my DC he would sit them down on their 18th and tell them why our marriage had ended. He said it because he hoped that they would disown me, given they hadn’t done before that.
I have never badmouthed him to them, even when they were reluctant to see him and when he put his new partner and step children ahead of them.
I won’t tell them about my affair, what goes on between adults in a marriage is between them. But if ex tells them his version, then I will tel them. And if they ask why, I will tell them a sanitised version of that as well. Because the full truth, how he isolated me from friends and family, how he gaslighted me, made me believe everyone hated me, insisted we had sex when I didn’t want, is something they don’t need to hear.
Interestingly he too had an affair at the beginning of our relationship but she dumped him so he stayed with me, and never admitted it anyway but I found out anyway. And the first person he slept with after we split was an ex who was in fact married, so he became the OM, oh the irony. But again, my children don’t need to know all that detail. What does it achieve to put them in the middle of a “she did/he did” type of discussion.