The "I Kissed a Girl" singer and the "Heartbreak Warfare" crooner began dating on-and-off in the summer of 2012. "John has always thought Katy was really sexy," a pal told Us Weekly. The couple split after two years in Feb. 2014. After opening up to Chelsea Handler, saying, "sometimes you have to go through all this s--t to get your grips on life," the songstress told Rolling Stone magazine in Aug. 2014 that she was no longer going to talk about her ex. "I don’t want to be rude to him…because it always comes to bite me in the ass," she said.