Survivor's Guilt: Asobinin no Koi

It's been 15 years, and yet every time Daisuke closes his eyes, as if etched onto the back of his eyelids, the tragic scene replays ruthlessly. The only other person who knows of his past is his coworker and best friend, Kengo, who sees past his playboy personality that he has adopted. As Daisuke slowly starts to accept that this is and will be his life, a fresh spring breeze blows in his direction, in the form of Kengo's little brother, a college student named Riku. Riku, traumatized in his own way, shows Daisuke a different way of living and forces him to confront himself, whether he wants to or not.

(Source: Torico)