"I know I didn't do it the right way," Rimes said in a clip from "Backstory: LeAnn Rimes," a 90-minute special which premiered Sunday and re-airs today and Tuesday on the Great American Country cable network. "I didn't have the tools to know how to do it the right way, how to let go the right way. I'd never been taught that."
The special comes as Rimes and Cibrian got married in a surprise private wedding ceremony Friday in California.
The pair met in 2009 on the set of their made-for-TV movie, "Northern Lights." The movie got more publicity for its off-screen drama than its on-screen plot, when rumors spread that Rimes, who was then married to dancer Dean Sheremet, was having an affair with Cibrian, who was also married and had two children with model Brandi Glanville.
"I have the strength [now] but I didn't at the time," Rimes said in the clip, posted exclusively on E! Online. "So, it got really messy, but I have learned a lot from that. And I'm not glad it happened, but I know why it did."
Months after the rumors first surfaced, Glanville left Cibrian and Rimes left Sheremet. Sheremet is now engaged to girlfriend Sarah Silver. Rimes and Cibrian got engaged in December.
"You had two couples whose marriages didn't work who really stumbled upon each other and fell in love," Rimes said, adding that she had no regrets.
Cibrian told Roberts, "We make mistakes and we learn from them, but we're human. We fell in love."
In the special, Rimes said she thought the country music industry was harder on her than it would have been for a male country artist who had an affair.
"[Country music] has such a double standard," she said in a clip. "You know, Willie Nelson and Johnny Cash and all these guys. God knows what they did back in the day. And if a woman did it, you never were accepted or forgiven. But if it was a guy, it was just their life. … It's quite interesting to have to navigate those waters as a woman in this business."
Rimes burst on the music scene in the mid-'90s. By 14, she had already made music history, becoming not only the youngest artist to be nominated for an Academy of Country Music award, but also the first country singer to win a Grammy for Best New Artist, in 1996.
With her career taking off, there was no time for a childhood. A nonstop schedule of shows and recording dates would gradually wear her down. She also developed a severe skin disorder over much of her body that would take years to control.
In her book, "What I Cannot Change," Rimes wrote about days she did not want to perform for anyone, but said when she wasn't doing a show, she didn't know what do with herself. When asked by Roberts who she was without music, Rimes broke down in tears.
"That was my life!" she said, crying. "I'm learning who I am without it and that's the coolest thing about my life right now that I have all of these incredible things happening and I have family and -- and I'm learning who I am without it."
"Backstory: LeAnn Rimes" airs on April 25 and 26 on the Great American Country channel.
ABC News' Alan Weisman contributed to this report.