Pink Heart Jam Beat, Vol. 1 (manga)

A drunken college dare to visit a brothel leads to serious romance when a now-former brothel beauty and his younger college boyfriend move in together!College student Haiga, now a senior, has finally moved in with his boyfriend, Kanae, a former classmate and brothel beauty who’s since graduated and joined the workforce. And although they’re living together, that doesn’t mean they aren’t both still busy with their own lives—Kanae with work and Haiga with his career aspirations. Noticing Haiga’s job search hasn’t been going well—and that they haven’t been on a date in a while—Kanae decides to take him out to cheer him up.

Unfortunately, even that doesn’t go well, and Kanae falls ill. But as the seasons pass, the two affirm and reaffirm their relationship, and before long, it’s time for Haiga’s final college performance—his graduation concert!