(Denise Truscello/Getty Images)

As a result of their affair in 2009, LeAnn Rimes and Eddie Cibrian have one of the most controversial relationships in Hollywood.

Rimes told Entertainment Tonight that she'd be lying if she said she didn't worry about Cibrian cheating on her. She said he feels the same way.

"Speaking for him, I would actually say that's creeped into his [mind]…I think we've been very honest and open with that to each other and our conversations about it have only made me understand how much he actually cares, as much as I do, about being faithful to each other," she said.

RELATED: LeAnn Rimes, 'Real Housewives' Star in Parenting Feud

Rimes produced her upcoming album, "Spitfire," during her affair, but she said a lot of the tracks were originally written about a friend.

"'What Have I Done' is one of the first songs that I wrote for the record, before anything was actually starting to happen," Rimes said. "It was written about a friend of mine, but I didn't realize I was writing it for myself at the time… It was my subconscious talking and I didn't know yet."

When Rimes' ex-husband Dean Sheremet first heard the track, she said, he perhaps knew they were headed for trouble.

"He actually heard the song when I wrote it and, actually, he knew what it was about before I did," she said. "He knew I was feeling feelings. I'm not sure what those were that he knew."

Rimes checked into a rehab center last summer to treat stress, anxiety and depression. The singer said she worried she might take her own life.

"I think any smart person would know that it is always a possibility that you could always get that sad and deep," she said. "I worried that was a possibility [but] I know I would never."

RELATED: Stars Open Up About Anxiety Struggle

She said there's only a handful of people who can understand what she has gone through from being a child star to having an adult career.

"It's hard to explain and I'm not asking for anyone's sympathy," she said. "I think when you see all these things written about you and what people are speculating you want to go, 'This is why' and it's just as simple and as complicated as I need to go learn how deal with myself and with the world because everyone is always looking in and I needed to figure out how to deal with it."