But in a series of comments to the press since word of the separation broke, Douglas, 69, has walked back rumors about the seriousness of their split.
Speaking to Jay Leno on The Tonight Show last week, Douglas said that he felt "hopeful" about the future of his marriage.
"I've been away for awhile, but everything should hopefully on the up and up," he said. "Sometimes people take a little bit of a break, but it doesn't necessarily mean that's the end. So I'm very hopeful."
Douglas told Berlin reporters in September that he and Zeta-Jones, 44, were in the midst of a "temporary separation," but weren't planning a divorce.
"My wife and I are fine," he said at the time.
"I wanna thank my wife Catherine for her support," the Behind the Candelabra star said onstage at the Emmy Awards last month, though she hadn't accompanied him to the annual event.