The Californication star and Tea Leoni - who have children Madelaine, 12, and Kyd, nine, together - have separated after 14 years of marriage, the actor's representative has confirmed.
However, according to gossip website TMZ, the pair are undecided on whether to begin divorce proceedings.
This is not the first time Duchovny, 50, and 44-year-old Leoni have split.
The pair went their separate ways in late 2008 amid claims Leoni received explicit text messages from her co-star Billy Bob Thornton, though both parties denied being romantically involved.
The separation announcement came shortly after Duchovny checked into rehab to receive treatment for an addiction to online pornography.
However, they reunited months later and even discussed renewing their wedding vows.
A source said at the time: "After so many ups and downs, they really want to recommit to each other. They're looking forward to a fresh start.
"They went through hell but somehow they managed to reignite their spark. David realises how close he came to losing it all so he especially wants to have their family and closest friends on hand to witness his second chance at happiness."