Jessica Simpson Spills on Nick Lachey Divorce and John Mayer Breakup In Memoir

Jessica Simpson's love life has been the subject of scrutiny ever since she and Nick Lachey opened up their home for the MTV reality show "Newlyweds." Now, in excerpts from her new memoir, "Open Book," she's revealing her side of things when it comes to her splits from both her ex-husband and ex-boyfriend John Mayer.

While the book doesn't come out until February 4, PEOPLE got its hands on a few preview passages from the tell-all. In addition to revealing she's a sexual abuse survivor -- as well as recovering alcohol and pill addict -- Simpson's relationships take center stage.

Simpson and Lachey tied the knot in October 2002 and launched their reality series the following year. In November 2005, they announced their separation, with Simpson writing that their "anxieties about our careers just seemed to feed off each other."

"We had been together almost seven years when I told Nick, 'I think I want a divorce,'" she continued. "I later heard that he told the press he was blindsided. I don't know how. At that point we were not even speaking to each other. Maybe he was just shocked that I stood up for myself. I don't think he ever thought I would take the leap."

This does somewhat echo what Nick told told Rolling Stone in 2006. At the time, he said that during their last months together, "we weren't fighting. It was just an overall state of tension. It was suffocating. And it just got worse and worse." He also added that he was "told" his marriage was over by Simpson.

Jessica went on to talk about her relationship with Mayer, which began -- innocently, she claimed -- before she announced her divorce. They met at a Grammy party in February 2005, with Mayer sending increasingly-intimate notes to her after. "As soon as I was single, he made his move," she said.

"He loved me in the way that he could and I loved that love for a very long time," she continued. "Too long. And I went back and forth with it for a long time. But it did control me."

She claimed that John "again and again ... told me he was obsessed with me, sexually and emotionally," but she often felt inadequate in the relationship. "I was so afraid of disappointing him that I couldn't even text him without having someone check my grammar and spelling," she added, saying that anxiety contributed to her alcohol dependence.

Simpson said Mayer broke up with her via email, but their relationship really came to an end after he called her "sexual napalm" in a now-infamous Playboy interview. "He thought that was what I wanted to be called," she recalled. "I was floored and embarrassed that my grandmother was actually gonna read that. A woman and how they are in bed, is not something that is ever talked about. It was shocking."

"I erased his number. He made it easy for me to walk away," she added, acknowledging that Mayer has since apologized for the comment.

"Open Book" releases February 4.