Britney Spears, who lost custody of Sean Preston, 3, and Jayden James, 2, to ex Kevin Federline, tells Rolling Stone her former husband isn't the best influence on the boys.

"They're starting to learn words like 'stupid,' and Preston says the F-word now sometimes," Spears says. "He doesn't get it from us. He must get it from his daddy. I say it, but not around my kids."

Spears is allowed two visits and one overnight per week with her sons. With her increased visitation rights, Spears is focusing more on motherhood these days, not partying.

"I feel like an old person now," she says. "I do! I go to bed at, like, 9:30 every night, and I don't go out or anything."