Shitenasasou de, Shiteiru Kanojo no Shiteinai Koto -Kimi no Hajimete ni Natteyaru- by Appetite - Adult Sex Game

The main character starts dating a girl. And then after a while she invites him home ...
When it comes to sex, the hero thinks he'll be her first... but there's no blood... Isn't she a virgin?
She confesses to him that she's been with a guy before. It breaks my heart because I thought she was a virgin... Jealousy...
- I want to be her first in everything, first sex at the pool, in the storeroom, behind the school...
And so began my search for my first time...