Kazuya's still having doubts. He's always been a man who couldn't do anything but worry unless everything was accounted for it seems. Mami's going to try and mess with Chizuru and try to gaslight Kazuya into thinking that Chizuru was making out with some guy on their compensated date. Chizuru won't say anything to Kazuya because she always plays with her cards to her chest and Kazuya's going to fall into self-loathing over the damage Mami left. Like an abusive SO, Kazuya will listen to Mami even though he knows better.
Or at least, that's my theory, a game theory (laugh track)