Coma: it actually has a bad ending like almost all the rest of the book, only that the english translator didn't bother translating page 196, which pretty much confirms she keeps cheating on him because (I think) he also fucks other girls.
It's one of those cases where you'd better stop at what they translate because like the Satomi and Satona book the afterstory 99% of times turns the ending to shit, not that the story was actually salvaged in any way by the final orgy, mind you.