@Buy5k
If a wife? Good, i know i won't touch her and divorce her. (No need to hire a PI or seek evidence, plain fact, she cheated, goodbye.)
As for the daughter? Yeah...That could be quite bad but at the very least i know and can have a talk with her.
It all depends. If everyone has it i doubt both women AND men would cheat as much and/or engage in hook up culture (like they do now). If only you know well then at least you can prevent sloppy seconds, cheating and might have some psychological advantage.