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Katy Perry is forthcoming about most things in her life, but there was one subject she refused to talk about for her new Rolling Stone cover: her ex, John Mayer.

"I don't want to be rude to him and/or what that was, because it always comes to bite me in the a** and I don't want to do that anymore," the "Roar" singer told the magazine.

That's a departure from a couple months ago, when Perry, 29, spoke to the July issue of Cosmopolitan magazine.

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She told Cosmo interviewer Chelsea Handler, "I'm living in the now and not fantasizing about the past. I have a lot of respect for [John] still, and I know it goes both ways. There's no bad blood, but I'm sure there will be inspired songs."

The pair started dating last summer and were off and on until finally splitting sometime in February.

Despite her breakup with Mayer, 36, and a failed marriage to Russell Brand that ended in 2012, Perry still believes she's better off with someone famous.

"It's not that they have to be famous, although there's a level of understanding when they're in the same business, you know?" she told Rolling Stone. "They understand what it means when you're tired from a show or the tour's exhausting you or if an interview went wrong. They know all the ins and outs, so you can just walk in to the house with a certain face and they understand, you know? Rather than, like, having to explain everything and that takes two, three hours."

Perry especially likes a partner who understands music, "because I love music," she said. "So anybody that understands the power of music, I'm usually instantly attracted to."