God damnit Hinata just say yesssssss why are you like this?! ><*
Mizuki, supporting Hazuki's love life is fine, but so is supporting your own, and if Hinata doesn't feel the same way about Hazuki then what is there to support?
Also, is cheating actually illegal in Japan, or is that just Mizuki exaggerating? Or a translation error?
Everything I can find says adultery is no longer a criminal offense, but it can carry
heavy social consequences, including being taken to civil court by the injured spouse (like, not just divorce, but actually suing the cheating partner & the one they cheated with), as well as just general community ostracizing because it's such a taboo in their eyes.
That said, Hinata being a minor is
very much a criminal matter, and so Mizuki would get the legal book thrown at her, on top of all the social fallout of her image in their community being ruined.
And, it would carry over and affect Hazuki, Mizuki's husband, Mizuki's
own parents (if alive), as well as Hinata's family. Social harmony and "public image & honor" are big deals in Japan, and this sort of thing gravely besmirches that, in a way that would cause blowback on even those only associated with the two offending parties. So realistically, if Mizuki gets found out...it would actually ruin her daughter's life, because she'd be painted with the stigma of her family member's deviancy and treated effectively like she is also a guilty party. (Or, she would at best be heavily
pitied by everyone, but would likewise still be 'other'd' by those who knew her, even if only by reputation.)