I’m not going to flame you @Callmebitterbut however your question is totally nuanced.
No one is saying to surpress your own feelings for the greater good. But there are so many factors at play. And whilst your feelings are valid and important, a child’s feelings are more so during, what is a very difficult situation.
The age of children is a very important factor in not sharing the details of any infidelity situation with DC.
My DC were 12 & 10 and are now 15 & 13. The 15 year old knows more now, than she did at 12. We have had age appropriate discussions about my emotions, how her dad leaving me flawed me (at the time) and that the OW was someone who made her dad happy, but me sad (again, at that time).
The discussions that then take place between you and your children over time adds more context as they get older.
There was a lightbulb moment for me in therapy when I said DC 12 wasn’t showing emotion, and the therapist asked me if I was showing it. I wasn’t. So we had a deeper conversation about the marriage breakdown. It was delicate, sensitive and importantly, age appropriate. I didn’t talk negatively about her dad or OW, but I shared how I felt - labelled the feelings eg lonely, grief at the life I thought we had, rejected.
As DC are older, they have a good relationship with OW, and yet they know that their dad did have an affair (this was something exH did not want to share with them). He doesn’t know they know, it hasn’t changed their relationship because it’s come from me in a very honest but sensitive way - timing was everything (we were playing a game on a road trip asking questions that we had to answer honestly and they asked me)
I am not saying don’t tell your DC. But be careful of the reasons why you are. If you’re doing it to change their opinion on their dad, it’s the wrong reason to. Share that relationships are complicated, love is hard, and people make mistakes. My situation is individual to me. Their dad is happier outside of our marriage, and now, I am happier too. we were not meant to be together. So what I may have told them 3 years ago, isn’t what I’d tell them now.