This is the prequal.
The sequal: https://zbato.com/title/191337-i-didn-t-mean-to-fall-in-love-double-official
Inexperienced Yoshino is about to turn thirty. He's nearly given up on ever falling in love, let alone having decent sex—until one day he steels himself and goes to a gay bar. There he meets Rou, a charming, silver-haired college student who is everything that Yoshino isn't: mysterious, assertive, and experienced with both men and women. Yoshino finds himself hopelessly attracted to Rou, as their awkward courtship simmers into something more. But is it love?