Warikitta Kankei Desu Kara.

Kaburagi Aya, a highschool student who is at the bottom of the school caste, and Kurosaki Sei, a teacher who was oppressed by a trauma from the past, get to know each other through a dating app. With ulterior motives from both side, the relationship between them gets distorted gradually...(Source: Ichijinsha, translated) Note: Includes an epilogue chapter and a four-chapter extra story