Jessica Simpson Was 'Saddened Beyond Belief' When Nick Lachey Moved On Shortly After Split

Jessica Simpson revealed new details about her divorce from ex-husband Nick Lachey and how she felt after he moved on shortly after their split in her memoir, "Open Book."

The new paperback edition of Simpson's 2020 memoir "Open Book" features a new introduction and diary entries, and one of the entries revealed the singer's reaction to finding out Lachey had started dating his current wife, Vanessa Minnillo, just months after they called it quits.

"So, Nick, you're with another already? Seems that you forgot the love you spoke to me," Simpson wrote in an excerpt shared by Entertainment Tonight. "I'm saddened beyond belief. Alone in the dark, with no one to call my own."

Simpson and Lachey tied the knot in 2002. But they announced their split three years later, saying in a statement obtained by People, "This is the mutual decision of two people with an enormous amount of respect and admiration for each other."

At the time, Simpson's camp claimed that she was fed up with his partying ways and refusal to join her family in Texas, but Lachey's side gave a different story. He was reportedly blindsided because she brought up divorce out of nowhere.

"She said, ‘I don’t know if this is working. I want to file for divorce,’" an unnamed source said, per People. "He was shocked. Nick was saying, ‘There are things we can do to work on this, and isn’t this worth fixing?’ And the answer was no."

Some have speculated that starring on the MTV series "Newlyweds: Nick & Jessica," may have been what led to Simpson and Lachey's divorce, but she said last year that this wasn't the case.

"I don't believe that the show is what tore our marriage apart," she explained in an episode of BuzzFeed News' "AM to DM" last February.

"Nick and I were very great at being together publicly and on-camera. We were best at our relationship when we were singing together. I felt like we were at home in that place," Simpson continued. "But as far as doing the reality show, we just kind of had fun with it until the end—until we started having marital problems."

More than a decade later, Lachey remains happily married to Vanessa, with whom he shares three kids — Camden, 8, Brooklyn, 6, and Phoenix, 4. Meanwhile, Simpson tied the knot with Eric Johnson in 2014. They also share three children — Maxwell, 8, Ace, 7, and Birdie, 2.

Simpson told Entertainment Tonight last year that she's glad they've both found contentment even if they had to do it apart.

"We both were at fault in a lot of things, but I'm happy for him now. He's married with three beautiful children," she said. "He took heartbreak and made it into something beautiful. That’s what I did as well, but it took me longer to get there."