Facinelli and Garth met on the 1996 set of the TV movie, "An Unfinished Affair." They have been married for 11 years and are the parents of three daughters.
"While we have decided to end our marriage, we both share the same deep love and devotion to our children. We remain dedicated to raising our beautiful daughters together. We ask for privacy and respect during this time," the stars' representatives said in a joint statement issued to People.com.
Facinelli, 38, is best known for his work in the "Twilight" film franchise, as well as the TV series "Nurse Jackie."
Garth, 39, was the star of the small-screen hits "Beverly Hills, 90210" and "What I Like About You." She also competed on "Dancing with the Stars" in 2007.