Michael Douglas and Catherine Zeta-Jones have split, rumors say, but representatives for both parties have refused to admit or deny the allegations. 

USA Today quotes Cece Yorke and Allen Burry, publicists for Zeta-Jones and Douglas, respectively, "Catherine and Michael are taking some time apart to evaluate and work on their marriage. There will be no further comment."

The couple of 13 years have faced some very difficult times during their marriage, and there are speculations that this could be the final straw.  According to People, the pair has not been photographed together since April 22.  Douglas was recently spotted in Sardinia while his wife was in New York with their two kids.

Zeta-Jones and Douglas created quite a buzz when they married in 2000, and had managed to keep their marriage together for over a decade. 

In 2010, the 68-year old actor battled throat cancer; and in 2011, the 43-year old actress sought treatment twice for Bipolar Disorder II, and again last April.  These, among other factors, have caused an ever-widening rift between the high-profile couple.

Peter Castro, deputy editor for People, spoke to ABC News and said, "Our sources tell us there were several factors.  It's undeniable that his throat cancer and her bi-polar disorder created a perfect storm of tension and issues that were really hard to overcome."

But it is speculated that a huge dent in the relationship was caused by what Michael said in his interview with The Guardian.  The "Fatal Attraction" star remarked that HPV was the cause of his throat cancer.  HPV or human papillomavirus is a sexually-transmitted infection that can be contracted through oral sex.

Castro said, "He gave very candid interviews about his sexual past that she really bristled at.  She was not happy about his comments and that sort of got the ball rolling in terms of the split."

So while each is evaluating and working on their marriage, they are, for the meantime, living separate lives.