"It's been years. Years," Lachey said when Cohen asked how he felt about seeing Jessica on TV. "Honestly, probably six years."
"It was like another lifetime ago," the 39-year-old added. The couple divorced in 2006.
Cohen also asked whether he ever sat down with his new wife, Vanessa Minnillo, to watch reruns of "Newlyweds: Nick and Jessica."
"As you can imagine, that's not popular viewing in my house. We don't sit around as a family and watch the old DVDs," he said.
Lachey was also shockingly candid about his relationship with Simpson's father, Joe, who is rumored to have had an affair with a 21-year-old male model and club promoter.
"The best thing about not having Joe Simpson as a father-in-law -- I don't have to play grab-ass under the table on Easter Sunday," he said.