At this point I'm not convinced it's even going to get all the way to full cheating (or at least the actual act of sexual infidelity, anyway).
She's apparently such a girlfailure and, as much of a pushover as he is, I feel like MC wouldn't actually commit at that point.
And if she truly likes him, she'd probably actually listen. She demonstrated that muscles alone wouldn't be enough to push her to it, by virtue of the start of this chapter - so, yeah.
This got real goofy honestly, but I guess I'll see where it goes. The wife got suspicious, and daughter saw the bite mark. So who knows what's in store, but I kinda doubt it's gonna be super toxic NTR stuff, at least with how weirdly inept and "maiden-like" she gets around him now.