Nick Lachey says "Newlyweds" hurt his marriage

Regarding "Newlyweds," Lachey told Letterman, "It was among the dumber ideas I think I've ever seen executed in history….For a while, I think we actually enjoyed doing the show as well. It was just so invasive that it became a problem." The talk show host then asked if Nick believed that his participation in the reality show was the reason for his divorce from Jessica. Nick answered, "You know that's one of those things where I think until you get enough hindsight and enough clarity and perspective, I don't think you can really know what happened. But, I certainly think it was probably a factor."

Lachey admitted that he has learned some lessons from his experience living under a microscope. "I think the biggest thing I've learned is there's a premium on keeping your private life private. And I think when you're in this business, there's always temptation to say more and say more and I think at some point, you have to draw that line and say, 'This is for me. This is for us. And that's for the public.'"

Nick is apparently applying these lessons to his current relationship with MTV VJ and "Entertainment Tonight" reporter Vanessa Minnillo. Though Nick and Vanessa have been dating for several months now, he refused to name her during the interview. Letterman attempted to get Lachey to admit to his romance with Minnillo, but Lachey would only say, "She will remain nameless. But she knows who she is!"