Jon has just filed papers asking a Pennsylvania judge for primary custody as well as a review of the child support order that is in place. Primary custody is currently Kate's, and Jon is required to pay $21,000 a month in child support.
Jon alleges that Kate "abuses" the terms of the custody agreement reached through arbitration, and has failed to document her child expenses, according to the court papers.
On Tuesday he threatened the suit, describing her as an "absentee parent" because of her stint on Dancing with the Stars, which shoots in Los Angeles. Kate retaliated soon after, saying she's "a single working mom [who] will do everything necessary to provide for my kids despite the opinions of others."
Who's side are you on? Tell us: