Juunen Ai: Decade of Love

Yuito had feelings for his best friend Shougo during high school but never acted on them. Ten years later, they meet again, and Yuito learns that Shougo is now in a relationship. Meanwhile, Yuito has a sexual relationship with someone else, which causes Shougo to become angry. Despite being in a relationship himself, Shougo confronts Yuito and confesses that he has always loved him.