Britney Spears's told her lawyer, Laura Wasser, to look into Kevin Federline's past bad behavior, as her custody battle heats ups, LIFE & STYLE WEEEKLY reports.

Britney Spears’s next move

“Kevin parties,� Britney told the insider. “He went out for almost two years straight, and now I’m the bad one? There’s no way I’m going to just sit here and let them take my kids.�

Britney’s vowed to change her ways. “She’s stepping up to the plate,� insists her pal. “She’s promised to bring her social life to a halt — no more clubs or late-night dinners. Instead, she’s going to spend every moment she can with her sons.�

But she’s made similar vows before, and friends are concerned it may be too little, too late. “Sean and Jayden are all Britney has,� says her pal. “They’re the only things that bring joy and any meaning to her life. If she loses them, there’s no hope for Britney.�