Lethal Dose of Love by Yosumi, Amber Tamosaitis, Dietrich Premier

He’ll never forget him―his ex-classmate Yuu, that is. College student Ryousuke was absolutely devastated when Yuu confessed and then promptly disappeared from his life without waiting for a reply. After desperately searching for years, he’s overjoyed when they suddenly bump into each other. But his happiness is soon eclipsed as he watches Yuu walk off into the arms of another man…