Curse to My Dear Friend

Hironobu, an average college student, is still haunted by what happened back in high school. He rejected a kiss from his best friend Tarou, and their friendship fell apart. Ever since then, he hasn’t been able to date anyone. In his mind, he calls it “Tarou’s curse.”
One day, at a group date he had been looking forward to, Hironobu spots Tarou for the first time in years. Hoping to avoid him, he tries to slip by unnoticed, but then hears a cheerful "Long time no see," spoken with the same bright smile Tarou had back then.

(Source: Ichijinsha, translated)

Note: Includes one extra chapter.