Harmon and Sehorn, who are parents to their daughters Finley, 11, Avery, nine, and Emery, five, got engaged in 1998 when he proposed to her live on 'The Tonight Show with Jay Leno', reported Ace Showbiz.
"For the sake of their children, they ask for respect and privacy as they navigate this time in their lives," Harmon's representative said.
Harmon has opened up about the difficulties of splitting her time between work and family.
The 42-year-old actress filmed her series 'Rizzoli & Isles' in Los Angeles while her family was based in Charlotte, North Carolina. She has also admitted that she and Sehorn struggled to keep their marriage strong despite the distance.