Rimes and the actor met and fell in love on the set of Tv movie Northern Lights in 2009 and their romance went public after surveillance video of them kissing at a low-key restaurant was leaked to media outlets.
The country star divorced dancer Dean Sheremet later that year (09), while Cibrian left the mother of his two sons, Brandi Glanville, so he could be with the Blue singer. They wed in 2011.
But because of their scandalous start as a couple, Rimes admits she does have concerns about her husband's fidelity.
She tells U.S. news show Entertainment Tonight, "Everyone else would think I am a liar if I didn't say yes (I worry about him cheating), and I have at times. It's definitely creeped into my mind, as it would anyone's."
Rimes reveals the actor, who was also recently accused of cheating on Glanville with waitress Scheana Marie, has the same insecurities, however she insists their relationship is going strong.
She adds, "I think we've been very honest and open 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. Where I'm at in my relationship with Eddie, that is not a worry that's in the front of my mind.
"I trust in him and I know he does me."
But she wishes she could go back and scrub out the affair she had with Cibrian when he was married to another woman, adding, "That's definitely not who I am. I definitely fell in love with someone and it's such an overwhelming emotion your body won't let you stop it... but I think both of us getting out of our marriages before we started a relationship would have been a better way to handle it."