's ex husband Peter Cook
has spoken of his regret of the affair that ended his marriage.
Brinkley filed for divorce after learning Cook had had an affair with an 18-year-old in 2004.
During a candid interview with Barbara Walters
on ABC show 20/20
, which aired in the U.S. on Friday, Cook admits he behaved like a "cowardly idiot".
He tells Walters, "I was a great father, a great husband. I failed as a human being. I failed myself.
"Christie is mad at me. She's entitled to be mad at me. I'm an idiot. I made a mistake."
Cook claims he knew his marriage was over when he began seeking attention from someone else.
He says, "I think the emotional aspect of our lives had changed. I think we were both feeling more like we were living with a brother and sister than a life partner.
"I realised my needs hadn't been taken care of, and I took the coward's way out and had an affair instead of approaching my wife and saying, 'Ya know what? I'm not happy.'
He adds, "I wanted a little acknowledgement, a little attention, a little thank you every now and then for my efforts, for the amount of time I took to care for her and my family, for the wealth I was building. Just the tremendous amount of work I was putting into my family."
The interview - which was taped earlier this week (begs06Oct08) - has angered Brinkley, who failed in her attempt to secure a restraining order against him, which would have prevented him contacting the couple's two children.
She claims that by opening up about their marriage problems, he breached a confidentiality agreement in their divorce which they settled on following a bitter public trial over the summer.
Their divorce was finalised in Suffolk County, New York on 3 October.