Gillian Anderson is single again. The former _X-Files_ star, 43, has parted ways with Mark Griffiths, her partner since 2006, her rep confirms to PEOPLE. They have two children, sons Oscar,

5, and Felix, 3. This is not the first serious relationship that has ended for Anderson. She split from husband Clyde Klotz – with whom she has a daughter – in 1997, and with second husband

Julian Ozanne in 2006.