So incessantly hitting on a girl so you can take advantage of any dips in their relationship actually does works in Japan, good to know.
Wait, if she knew all along, and she's on good enough terms with MC that they chat and he has a nickname for her and she lives with his grandparents, why the hell didn't she tell him in the first place???
Unfortunately, like all cases of this story, if they're cheating on you at this stage there's no realistic way you'll get them to like you back again enough to hurt them. At least with the double NTR series they did a public reveal, which hurt their public reputations, and in that one other NTR story there was police action threatened bc MC tried to kill himself. But unless (MAYBE) you're married, they aren't going to regret shit.
I really hope it won't be a plot point that his grandpa tells Kayo he brought another girl over and gives her the leverage she needs to accuse him of cheating instead and break up with him.
