"He is really, really sick. In the past two months he's spent six weeks in the hospital. He's had ruptured diverticula and he got a colostomy, which got gangrenous. He's had [several] surgeries."
The 43-year-old space center missle-support specialist from Rockledge, FL was the only The Biggest Loser: Couples contestant not in attendance at the live finale, and all host Alison Sweeney told viewers was that Marks was "too ill to make the trip."
However according to Fields, her ex was instead suffering from an infected colon.
"I'm sorry that he can't be [here]," she told TV Guide. "He was truly missed."
Despite no longer being married, Fields said she decided to compete with Marks on The Biggest Loser because he was "the biggest guy" she knew and also a "tough competitor."
"Paul is a good man," she told TV Guide. "He always loved me. I was the one that just couldn't be in the marriage. I'm truly blessed that he still loves me. He'll make a good husband for somebody, but we're better off friends than we were as mates."
After leaving The Biggest Loser: Couples campus as one of the fifth season's two finalists, Fields learned she had a herniated disc yet continued to train for the show's live finale.
"I knew I could overcome this," she told TV Guide. "As you watched this show, how many times was I the underdog and I overcame it? I worked with an excellent trainer and if it hurt, I didn't do it. The only thing I could find myself doing was the step mill and the elliptical machines. I did those for four or five hours a day."
Fields began the competition as the fifth-season's heaviest woman at 271 pounds and lost 109 pounds for a 40.22% weight-loss percentage.
While she had initially hoped to lose the weight so she could become pregnant, Fields told TV Guide it's too soon to think that far ahead and she's simply ready to get her new life on track.
"This has been my focus for five months," she told TV Guide. "I really need to get back to work, I need to get my life back and go from there... I've had family, and some people were nice enough to loan me money to keep me out here. Now I need to get them repaid. I'm available for hire if anybody wants me."