Mada Nakunatteinai Hito

Haruka Kawarazaki, a young man aspiring to be a manga artist, and Mayuko Kawarazaki, a beautiful woman to whom everyone looks back. They live in a room in a flat, share a meal every night, and lay on each other's skin. But they are not husband and wife. A woman whose heart has been broken and a young man who knows it but continues their relationship—a love suspense about a forbidden relationship that you can't stop even when you know it's wrong.

(Source: Yoru Sunday, translated)