Jessica Steindorff (Photo) & Jason Trawick Having An Affair Behind Britney's Back?

Earlier this year, there were some rumors floating around that Jason Trawick was cheating on Britney Spears. The story was then written off as a rumor. But today, Star magazine is reporting that Jason has been carrying on a long-term affair with an actress named Jessica Steindorff.

Jason reportedly met Jessica Steindorff in 2007, before she briefly took a job as his personal assistant at a Los Angeles talent agency.

Jason's affair with Jessica cooled off when he started dating Britney in May 2009. But that didn't last long. Soon they began rendezvousing for sex dates at his Bel Air home or her Hollywood apartment.

"Jason has been cheating on Britney with Jessica from the beginning of their relationship," a friend of Jessica tells Star. "He has deceived Britney with his lies for too long, and somebody needs to tell her the truth, even if it hurts."

"He was always telling Jessica that he had broken up with Britney so it was OK that they were sleeping together," the friend tells Star.

The tabloid claims to have secret emails exchanged between Jason and Jessica to back up their story.

In other Britney news, the singer has been accused of sexual harassment by her ex-bodyguard Fernando Flores.

Poor Brit, she just can't catch a break!

Pictured above: Jessica Steindorff, below- Jason, Britney and her boys.