>>8547601 (OP)
There is this eromanga about this dude in high school that is dating a girl a year older than him.
They have a great relationship and work in this restaurant, movie theater, I don't remember...
A new manager arrives to this place and becomes friends with the girl. He gives her advice and looks after her, in reality he wants to fuck her.
One day the manager tells MC that his girl called him immature and unreliable behind his back (lie), at the end of their shift he leaves angry and bails out on their date.
The manager tells her he will take her out to dinner and listen to what she has to say. After the dinner they start to drink, the manager doubles down on MC being useless but the girl is not having it. However he gets the girl drunk and seduces her promising a one night stand.
The girl feels like a piece of shit and starts avoiding MC so the manager seduces her over and over, fuck every now and then even during work. She starts to get hooked on the sex but refuses to break up with MC.
Eventually manager calls MC and convinces him to hide in this storage room to learn something about the girl, dude brings her inside and fucks her while she doesn't know MC is there.
MC breaks up with her while she is confused and angry because what manager did. She has no excuse but she accepts to be with the manager since he said he loves her and she believes him however something is up with her.
Eventually she dates manager who convinces her one day to go on a trip. Excited their arrive to this villa where men and cameras are waiting for them. He then reveals that he owes money to a yakuza dude and he agreed to let her fuck them to pay the debt. She accepts without asking much.
The girl knows already: the manager never loved her and she knows he has no debts he is basically whoring her. Despite that she agrees, knowing she deserves this suffering, her life is ruined now.
MC moves into a younger innocent girl.
To me that's a good ending.