Katy Perry is once again a single lady after breaking up with her rebound rocker beau, Florence + the Machine guitarist Robert Ackroyd. The pair weren't a pair long, only going public with their coupling last month, kissing at Coachella. Guess things went south shortly after. "It wasn't serious," a source said. "She likes him a lot, but it was just a distraction. It was very short-lived, she's still dealing with getting over her marriage ...