OH!!! This didn't go the way I worried it would, and I am so happy. This is a side story to Yukidoke no Koi. Several years after graduation, Oushirou still harbors feelings for his childhood friend Koba, who is moving to Tokyo for work and will live nearby. One afternoon Oushirou drops his wallet. It's picked up by a regular at the bar he frequents. After talking a while, the man - Inamura - offers his contact information and drops the fact that he's gay. He figures out that Oushirou is pining for Koba and offers to be a distraction.
I worried this would be a situation where the childhood friend wises up and dates the main character, but it didn't play out that way. Koba and Oushirou remained dear friends, and Oushirou began a relationship with Inamura - moving in with him five years later.
Content warning: There is a reference to one-sided love between brothers, but it is only spoken. We see nothing and nothing comes of it.
I WOULD LIKE TO ADD! This is the FIRST! manga I've ever read where the characters have a frank, honest discussion about sex before they have sex. And then after sex, evaluate what happened, and one reassures the other that if bottoming isn't his thing, they'll work something out - that sex isn't everything. I've never seen that and it was totally refreshing and wonderful. Thank you to this author.
Bokura ga Koi wo Ushinau Riyuu