It's an anime based on eroge visual novel.
What make it kind of different with the other eroge is when you get bad ending, it's truly bad.
The anime adapt the vn based on one of heroine route and the ending is a bad end.
Basically it's a story about a main male character who can't control his sexual drive and start sleeping with the other girl behind his girlfriend knowledge. And the other girl is the mc girlfriend best friend.
In the end the gf kill the other girl and the mc.
In the manga adaptation, the other girl kill the girlfriend and mc.
The odd part is that up to episode 6, minus the end of that episode, it was fairly standard love story that almost worked into the argument of energetic male character don't work with shy female character. Like Hinata can't work with Naruto, so he ended up with Sakura. However, the end of episode 6 and up is where things turned for the worst. It's where the director thought it would be historical to do the route of the boy being sex addict. Sad, just when I was about to use that series as an argument of what matched and what don't.
I understand, thanks for the answers.