From this interview by Meghan Ward:
MW: Knopf published your bestselling memoir, The Slippery Year, yet Wife 22 is being published by Ballantine. Why didn’t Knopf publish Wife 22?
MG: Knopf passed on Wife 22. The bottom line: It just wasn’t the book they wanted. However Wife 22 then went on to sell to Ballantine in the U.S. (the winner of a three-way auction). Then the movie rights sold to Working Title Films. Then it sold in 30 more countries. So it just goes to show you that even if your book isn’t one publisher’s cup of tea it doesn’t mean another publisher won’t love it.