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"She discovered through her friends," an insider told Us of how Perry learned out about Russell's collection of rebound romances. "One of the women told a friend of hers and it got back to Katy."
Russell's reported sexual escapades may even result in a new relationship in the very near future. Apparently, there is one woman in particular who has tickled his fancy enough to encourage him to "explore a relationship" already. "[Russell] told her he wanted her to move in with him after the divorce is final," the source said.
And Russell's alleged insensitivity doesn't stop there. To add insult to injury, he has been trashing Katy, bad-mouthing her behind her back to his various sexual partners. "He's spoken terribly about Katy to them," the insider revealed.
Meanwhile, Katy has committed to her first public appearance in the U.S. since the divorce announcement. After wrapping her California Dreams tour overseas and pulling out of the People's Choice Awards earlier this month, the singer is set to co-host the GiveLove charity event at 1 OAK nightclub in Las Vegas tomorrow (Jan. 27).