Only read 1 chapter.
Guy had onesided love with his friend.
Guy is adult now working as a student teacher in a HS and meets his love's nephew or smth who looks exactly like him.
This is kinda like a replacement story to me.. Where can a story like this even go?
The only good i see coming out of this is if this experience somehow gives him the courage to confess to his actual love (not the replacement)..
Omi-sensei no Binetsu