Sabi no Yume Hidari

Toshio, who was created by modifying the body of a boy into a cyborg designed for sex, was taken in by Shindou, the person who takes care of him. Toshio spends his peaceful days doing chores, and waiting for the arrival of his beloved Shindou. However, while cleaning up Shindou's belongings after they move out, Toshio happens to find a picture of himself in a school uniform with a girl he doesn't recognize...

(Source: Printemps Shuppan, translated)