As Taka says, meh ending. Quite the lackluster. It seems that the rape and blackmail scenarios that were depicted are still more acceptable than a wincest.
This is like that story of the guy that broke both his arms, and ended having sex with his mom.
But waaaay less fucked up. This actually end with a happy ending, which as everyone else said, is not the reason why this manga exist.
We were here for the debauchery and the eventual depravity of wincest.
@firefox1234 Is not from a manga, is an allegedly real story famous in reddit, quite old too by now from 8 years ago, and it became kind of a meme.
https://www.reddit.com/r/IAmA/comments/nmmjr/iama_man_who_had_a_sexual_relationship_with_his/