The bath sequence is exceptionally hot. Eri is obviously aroused when Shin forces her to suck his cock while she's shampooing her son. As with the cheating, it's the sheer reckless wickedness of the act that truly arouses her.
Well...I suppose that's an accurate title.
Still...What a nice kid. He's playing wingman for our protagonist...Unknowingly, but still.
I guess I feel a little bad for the husband. I mean, not only is she cheating on him, but she admits that he can never get her off? Brutal.
That ending though. Hahah, good one, kid.
Another time, place and artist, Yuusuke would have already told his father how much (a-hem) "fun" it was to bathe together with Mom and Shin-nii ... if Dad had the necessary (a-hem, again) "testicular fortitude", he'd be reaching for the family katana once he got home ... and it would NOT be to use it upon himself.
Hoping this is not another case of Art Imitating Life, where "... the names have been changed to protect the innocent".