In her new autobiography, "Deep Thoughts From a Hollywood Blonde," the 41-year-old actress said the marriage had been crumbling for several years before the two divorced.
"My husband was away a lot then, working across the country on location on a film that he'd written, was producing, and was starring in," wrote Garth, who was mostly a stay-at-home mother at that point, raising their three daughters at the family's ranch outside of Los Angeles. "I was thrilled for him that he was taking his career to the next level, but I was also, I can see now, feeling a bit resentful and itchy in ways that I couldn't quite identify. … All I know is that I felt like I was waiting: for him to come home, waiting for him to be free to join me in the day-to-day of our family life, waiting for the next job to be lined up that would take him far away from us again," she wrote.
"The ground that had been cracking and shifting finally split open and pretty much swallowed me whole: Peter came home, and told me that he didn't think he wanted to be married to me any longer, and he thought it best that we separate so that we could get a better sense of where we stood with each other," she wrote.
Garth said writing the deeply personal book was something of a challenge.
"In some ways cathartic and very eye-opening for myself in a good way to sort of take a look and see how my life has progressed," she said. "All the things that have sort of happened and how they've molded me into the person that I am today,"