Britney Spears was furious when she discovered her ex Kevin Federline out partying with his ex, The ENQUIRER reports!

Britney Spears furious when she discovered her ex Kevin Federline out partying with his ex

Kevin Federline and former GF Shar Jackson - mom of his two oldest kids - hit the Madden 09 video game launch party while Britney Spears was stuck at home, caring for 2-year-old son Sean's ear infection.

Although Britney knew Kevin planned to go to the vid game kickoff, when she discovered he was with Shar, she went ballistic!

Brit called K-Fed repeatedly while at the party, leaving him panicky messages. She told him that she didn't remember what meds Sean had to take and that he was whining constantly for dada.

"Britney was even asking how to work the thermometer to take his temperature," the source revealed.

Image WENN

By Fabien Montique posted time [ 1:40 PM]