Hirugao

Natsuhiko is a mature, down-to-earth college student who’s secretly gay and has had a crush on his best friend Yuusuke since high school. Yuusuke sometimes gets a girlfriend, but the relationships never last, and he mostly hangs out with his guy friends. Being just a friend felt pretty comfortable for Natsuhiko, but now things are starting to change?!

(Source: Tokyomangasha, translated)