On Friday, it was David Letterman's turn to open up in front of an audience.

The "Late Show" host, who late last year was embroiled in a $2 million extortion plot stemming from his affairs with female members of his staff, made a rare guest-star appearance, saying on "Live! With Regis and Kelly" that he's now focused on repairing his relationship with wife Regina Lasko.

"Because you think an explosion has taken place and you're looking at the shards and you say, 'Well, can we put this back together?' " Letterman said. "And by God, maybe you can put it back together. And maybe it won't be the same, but maybe it will be different, and maybe it can even be better in a different way."

Dating since 1986, Letterman and Lasko -- the parents of a son, Harry, born in 2003 -- married at a surprise wedding in March 2009. Seven months later, the comedian admitted to his CBS "Late Show" audience that he had been unfaithful and was the target of the extortion.

Letterman also later issued a public apology to Lasko.

Speaking to Regis Philbin and Kelly Ripa on Friday, Letterman, 63, didn't mince words about his mistakes and the harsh toll they've taken on his family and himself.

"It was stupid behavior," he said. "And you take a look at the explosion, and it knocks you down and you wake up every morning and you're scared and you're depressed and sad, and you kind of got to let that knock you down and knock you down."

He appears hopeful for brighter days. "And so right now, that's what we're doing, we're putting the thing back together to see what it's going to look like," he said. "And is it viable? Is it something that can be satisfying and fulfilling?"

Letterman also expressed his appreciation for the support he's received during his struggles: "I've had nothing but great friendship to help me through this."