I remember reading a H Manga about a wife/mother who has never been sexually satisfied. She cheats on her husband and is tricked into porn and finds even professionals can't get her to cum. It has 2 chapters and in the second chapter I think a fat professor with a MC goes out of his way to find her and contact the person(glasses wearing woman) who recorded the porn. The professor ends up either exhausted or his dick broke. (Not sure but I think the woman's name was keiko?)