It's a Detached Relationship.

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