The country singer wed the Oscar-winning actress in May 2005 after a whirlwind romance but split four months later and Kenny says the union was doomed from the start.
He said on 'The Oprah Winfrey Show': "It was out of the box. Oh my God, but it's tough. It really is tough. And she's a sweet soul, No Doubt about it, but I just wasn't ready. This is the first time I've actually talked about it, but that's what happened."
Following the nuptials, Kenny confessed he "panicked" as being married didn't fit into the life he had created.
He said: "I panicked. I look at my life as a box... So everything that I put in - learn how to play guitar, put that in the box. The friends I made. I put that in the box, and my career grew. That box I built grew into this wonderful house. And you protect everything and all the relationships and all the people that helped you build that house."
Kenny is currently dating nurse Amy Colley and says he has taken a break from touring as he wants to spend quality time with her.
He told People magazine: "It's not like I'm taking a year off so I can get married again, because that could or couldn't happen. But I want to put myself in a position to do it if it did happen. I want to put myself in a position to have a relationship in my life."