Typical, guy in love with his long time friend, but doesn't tell him.
He has another guy, a very long time sex friend. for many years, he goes to him whenever he is down.
Later, the other guy figures out his feelings and they sleep together, but it also becomes a sort of off threesome.
The sex friend moved away, but the other guy was so upset about him being gone, his lover went and found him and made them reconcile.
They went to a hotsprings together too. the lovers were fighting, and the sex friend got involved and they made up pretty quickly, all having sex
Koitomo Triangle