I have found out some info that a man had a threesome on his stag do, over a decade ago. I don't know the wife, and only know of the husband through friend (this friend was on the stag do). They have since had 3 children and are happily married as far as I know. Not sure what to do. I would want to know if it was me, but I don't want to set off a bomb in her life either. Shall I do anything, or just leave it?