since my example is freak ass. let me change it to normal one then.That is some freak ass logic
this girl know FMC's true nature and choose to get dirt on her simply because her petty jealousy. her family and her life sucks while crazy FMC managed to keep her "perfect girl" image on.
in order to do it, she involved FMC dad(innocent guy who didn't know shit) by making up to look like adult then waiting and set up situation ,trying to create "married man who cheated" thing then record it and she gonna get outplayed by her own video.
It's truly "fuck around and find out" isn't it?