Cibrian and Rimes recently separated from their respective spouses amid talk they were having an extramarital affair. The couple was photographed together looking cozy during a golf outing and a concert in the past week.
"He's just somebody I don't know," Cibrian's wife, Brandi Glanville, told People magazine.
"I don't understand," she said. "You think you know one thing and you wake up and it's all been a lie."
Glanville admitted the separation has been difficult to explain to the couple's sons -- 6-year-old Mason and 2-year-old Jake. She said they are happy to see him when he visits.
"I'm just like: 'You know what? You're not the man I married,'" she told the magazine, adding she spoke to Rimes twice recently and told her, "He's all yours."