Report: Jamie Lynn Spears' Fiance Cheated While She Was Pregnant

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Jamie Lynn Spears' fiance was cheating on her while she was pregnant, the self-proclaimed other woman tells In Touch magazine.

Kelli Dawson, 28, says she and Aldridge, 19, were sleeping together when Jamie Lynn, now 17, was six months pregnant with his child.

Dawson tells In Touch that Aldridge began pursuing her in late 2006, when he was already dating Jamie Lynn.

“He totally instigated it and pursued me," Dawson tells the magazine.

The couple saw each other a few times and “kissed randomly,” but it wasn’t really “hot and heavy,” Dawson says, until the spring of 2007.

“Kelli and Casey have been a couple on and off for a few years,” Britney Spears’ first husband Jason Alexander told the magazine. “They were a really tight couple, but I think it was hard for Kelli, having Jamie Lynn in the picture.”

Dawson says she and Aldridge stopped sleeping together a few months before Jamie Lynn gave birth to their daughter, Maddie.

“It just didn’t feel right,” she explains. “He had to deal with the baby coming, and it had to stop.”

Click here for the In Touch report