The 70-year-old actor had suggested that his throat cancer could have been caused by oral sex and made front-page headlines, reported E!Online.
"It was one of those things... And I so regretted any embarrassment that it caused Catherine. And her family. We had a little bump in the road. The problem in this business is that everything is so public," he said.
In fact, the couple ultimately split in August 2013 but not before reconciling and getting back together months later.
Douglas also feels extremely grateful for his great health and surviving the disease truly gives you a new outlook on life.
"I was just happy to be alive. I was ecstatic," he shared when recalling his battle. It feels like a rebirth after you go through cancer and you come out of it. You feel like you're a child.