LeAnn Rimes stopped by the 'Tonight Show' this to debut 'Borrowed,' also giving show host Jay Leno a rather candid interview about penning the brazen lyrics of the first single from her forthcoming album, 'Spitfire.'

"I call myself pathetic in the song and I loved that word because it was the only way I knew how to describe myself," Rimes told the host of the inspiration behind the song. "Because I was pretty pathetic."

Adding to her tell-all moment, she shared, "I actually still get embarrassed talking about it, even though I've written a whole album about the situation. I did go through a very public affair with Eddie, who's now my wonderful husband. People who haven't been in that situation, I guess, look into the darker moments of things. I think a lot of people think it's done with complete abandonment and it wasn't."

Rimes hasn't always been comfortable with full disclosure of her rather public affair with her now husband, actor Eddie Cibrian, but admits that the therapeutic writing process of her new album has made opening up about her personal life a little easier.

"I actually carried that lyric, 'I know you're not mine, only borrowed,' around with me for about eight months," the singer reveals. "I was afraid that if I wrote it, I would have to write it so honestly that I would offend, more so than I already had, everyone. I knew also that there's a lot of humanity in the truth that this is how I felt, because a lot people, I think, wanted to put words in my mouth as to how I felt. This is the truth, this is how I felt, and there's no beauty in it."

Rimes may be coming to terns with her personal demons, but Cibrian's ex-wife, 'Real Housewives of Beverly Hills' star Brandi Glanville appears nowhere close to a reconciliation with the stepmother of her two sons. In fact, recent twitter outbursts from Glanville have further fueled the feud between the two tabloid regulars.

"There's no reality in a reality show," Rimes says in reference to Glanville's reality show gig. "I guess it's not weird when I know that's not my reality. Here's the therapy coming out in me; the positive, I should feel flattered that I'm that interesting. That I can be such an amazing storyline on a reality show."

Fan hoping to get the full story of Rimes whirlwind romance with Cibrian will have to wait for the release of 'Spitfire,' which the singer claims is the most honest songwriting of her career. The 14-track album is expected to be released in early 2013.