FWIW- I'm guessing the time to have this conversation with them is when they are inbetween relationships (if that ever happens). They're too hopped up on that new relationship high to have these considerations for their kids (I can't tell you how judgemental STBX used to be about other people's situations, and now look at him - it's just evidence that he isn't completely in right mind).
That's my plan anyway....if that opportunity ever comes to pass.
The day I discovered he had been living with OW since BD and he came to my daughter's soccer game- I literally put my hand up and told him to spare me all the excuses about there being issues with the marriage and that it was clear that his actions were about one thing only. I then told him to do some research about how bad it is for kids to be exposed to their parent's new romantic partners too soon. I doubt he took me up on that....That's as close as we've ever come to having a conversation about it.
