I'm going to be a little vague to avoid being identified but basically someone close to me has decided to not only cheat on their partner, but to do it with their stepchild's ex and co parent. They aren't with the stepchild's other parent any more, but the step parent/step child relationship has still been maintained for many years.
The stepchild HAD an amazing relationship with their co parent - or so they thought. Obviously it has caused massive upset, step parent and their affair partner are adamant that it's been years since both marriages ended so the only thing they've done wrong is cheating on their current partners and stepchild is the devil personified for being upset. I don't agree, if someone i still referred to as my step parent slept with my ex/co parent I would be devastated.
I won't offer my opinion unless asked but I've been friends with the step parent for many years and I am just disgusted. AIBU to just back away completely? I can't look at my friend in the same way ever again.