Eric Johnson Cheated on Jessica Simpson With Ex-Wife?

Eric Johnson has been accused of cheating on Jessica Simpson with his ex-wife Keri Johnson, according to a report.

An alleged friend of Keri's claims that the former NFL star was still involved with her at the time when he began dating Simpson, 31. Johnson has since divorced Keri and is now engaged to Simpson.

"He's a two-timing cheat! He was still having sex with Keri after he started seeing Jessica. She needs to think twice before marrying him. He's already cheated on her once - he'll most likely do it again," the unidentified friend reportedly told Star magazine.

Johnson, 33, reportedly met Simpson in 2009 at a mutual friend's house in Los Angeles, where he had allegedly brought Keri, his wife at the time, along as his date. He and Keri, a freelance stylist, separated in October 2009 after five years of marriage and Johnson began dating Simpson approximately six months later.

This is not the first time that the couple has been faced with alleged relationship woes. In May it was claimed that the pair, who welcomed the birth of their first child on May 1, were growing apart due to the challenges of having a child.

"[Jessica] got so emotional that she lashed out at Eric, telling him she doesn't want to get married anymore," a source previously told OK! Magazine. Simpson reportedly no longer has time for her fiance, according to their reports.

"[Eric] first met Jessica when she was in a more easy-breezy part of her life, where she wasn't constantly having to worry about call times and scheduling conference calls to promote [Fashion Star]," the insider went on.

The couple of two years announced their engagement in November 2010 and was forced to postpone their anticipated November 11, 2011 wedding date due to Simpson's unexpected pregnancy. They are yet to set a new wedding date.

"It won't be this year," Simpson told talk show host Katie Couric. "I really want to do a big, fun wedding with my friends and family."