Kenny Chesney and Renee Zellweger's whirlwind romance only took a mere four months to lead to marriage in May 2005 – and only four more before Renee filed for an annulment.
On Friday's "The Oprah Winfrey Show," the country star told Oprah he "just wasn't ready" to make the commitment.
"I panicked," he explained. "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 built grew into this wonderful house… And you protect everything and all the relationships and all the people that helped you build that house."
However, the country star said his brief marriage didn't make its way into the box.
"It was out of the box. Oh my God, but it's tough. It really is tough," Kenny said. "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."
However, things are looking up for Kenny, who told People in a separate interview that he hasn't "felt this content in a long time."
The singer told the mag he had realized his grueling schedule of touring and recording – including five Billboard No. 1 albums — hadn't left him enough time for himself or his relationships.
"Someone said, 'You sure do give a lot of your life to this.' And I said, 'No, this IS my life.' There's no room for anything else," he added. "And that's gotta change."
Kenny has been dating Amy Colley, a Nashville nurse, since 2008, and said she's one reason why he's staying away from the road.
"It's not like I'm taking a year off so I can get married again," Kenny said. "'Cause 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."
Related Content from AccessHollywood.com:
VIEW THE PHOTOS: Country Stars
VIEW THE PHOTOS: Celeb Groupies: Stars Who Love Rock N' Roll Stars!
PLAY IT NOW: Kenny Chesney Talks 'Lucky Old Sun'
PLAY IT NOW: ACCESS EXTENDED: Country Music Awards
MORE ACCESS ON THESE TOPICS: Kenny Chesney - Renee Zellweger - Oprah Winfrey - Former Couples - Country Music