Gillian Anderson and Mark Griffiths

Gillian Anderson has called it quits with her partner of six years, Mark Griffiths, People reports.

Anderson and Griffiths, who never wed, started dating in 2006 and have two sons together, Felix, 5, and Oscar, 3.

Check out photos of Gillian Anderson

Anderson, 43, has been married twice before. She and art director Clyde Kotz, with whom she shares daughter Piper, 17, divorced in 1997 after three years. Anderson then married documentary filmmaker Julian Ozanne in 2004 before splitting two years later.

The X Files alum can next be seen in the BBC miniseries The Fall.