When asked about the subject, Pete told Radio One host Chris Moyles: "I did what I had to do." The 36-year-old wouldn't go into exact reasons behind the break-up, but he did admit there was more than one.
And regarding the question of whether he thought they would get back together, he said: "What's done is done. She's the mother of my kids and there'll always be a lot of love there, but that's it."
When Chris suggested living with Katie must have been difficult, Peter showed his support for her. "For every bad (thing) that somebody has, there's a lot of good," he said.
The singer's appearance on the programme was scheduled to unveil his new single Behind Closed Doors, which he wrote five months ago and will release on August 10. And accompanying him were the video cameras of his reality show, which he has recently resumed work on and will continue with for the next twelve months.