Kiss And Tell: Ex-Boyfriend, Ray J Exposes Kim Kardashian's "Bedroom Secrets" In His New Book

In the midst of a nasty divorce, Kim Kardashian gets another devastating blow as ex Ray J reveals intimate details about their relationship -- from her bedroom skills to her over-the-top spending-- in his new tell-all book.

"You just want to tell the truth," the book's co-author, Maxwell Billieon, tells Life & Style. "So that's what we did."

Death of the Cheating Man alleges that "KK," as Ray J calls her, pursued him and slept with him while she was still with her first husband, Damon Thomas, in 2004. While Kim has denied cheating on Damon, the shocking revelation may give Kim's estranged husband Kris Humphries more ammunition for his case, supporting the notion that Kim never intended to commit to her second hubby.

"She let me know she wanted to get with me," Ray J, an R&B singer, recalls in the book. "She left her husband for me as soon as we started having sex."

Ray-J also reveals intimate details from Kim's how-to-win-a-man manual, like greeting him with hot towels and toothpaste on his toothbrush in the morning and lingerie fashion shows at night. The attentiveness grew to be too much, though. "She wanted to know where I was at all times," Ray J writes. "She literally thought I was cheating with every girl I ran across."

To Kim's horror, her onetime beau was, in fact, sleeping around, but Ray J suspected his jealous girlfriend was cheating, too. "I had no respect for her," he harshly admits.

"Kim's putting on a brave face, but she's furious about Ray J cashing in on her," a friend tells Life & Style. "There's so much that has gone wrong for her this year -- he's just another person trying to humiliate her."