After Adam Levine shut down cheating allegations in his current relationship with Behati Prinsloo, a throwback interview with the Maroon 5 frontman resurfaced, in which he admitted to being unfaithful in the past. "Instinctively, monogamy is not in our genetic makeup. People cheat. I have cheated. And you know what? There is nothing worse than the feeling of doing it," he told Cosmopolitan back in 2009.