Manga Domestic Na Kanojo

Natsuo's losing his virginity tonight. His partner? Her name is Rui, and he only met her today after school. It was she who raised this whole situation, saying that she wanted to just get knowledge of sex. She doesn't want a relationship, and she doesn't care about Natsuo. After that, Natsuo feels guilty for losing his virginity with a girl who he does not even like especially. Basically, this makes him feel that he has betrayed his love to his school teacher: Hina. The bizarre story of a love triangle unfolds when Natsuo, Rui and Hina become part of the same family!