The 43-year-old actress, who just finished treatment on her problem, credited her family and close friends for helping her overcome the ordeal, the Ace Showbiz reported quoting Stella magazine.
"When you get sideswiped like that (Douglas' cancer diagnosis), it's an obvious trigger for your balance to be a little bit off - not sleeping, worry, stress. It's a classic trigger," Zeta-Jones said.
The actress said her husband's diagnosis came as a "huge shock".
"I thought I didn't have the tools to cope. But it's amazing where the strength comes from - from family and friends, from strangers supporting us," she added.
More From This Section
"He's a very matter-of-fact person. Once he was diagnosed he was like, 'Okay, what do I do?'... It was very intensive ... But he still retained his sense of humor.
"He was very open with the children. No secrets - they went and saw him having treatment. Together we all coped with everything. It did make us closer. But I wouldn't wish it on anybody."
Douglas, who declared that he was cancer free, recently caused a stir by suggesting that oral sex may have contributed to his throat cancer.