"Lust is a God-given desire that's gone haywire," he said. "And I would say the sexual desire in marriage can light that fire that keeps the marriage together."
But in the case of lust, Young said, this desire is wrong.
"You look at someone -- you think and you picture having sexual relations with that person," he said. "Too many people unknowingly, ignorantly, say, 'You know what, we're just dogs in heat. We can't resist it. We're going to do what we do. Boys will be boys, girls will be girls.'"
Young also took aim at Biderman's Web site, saying, "What if I supplied all the bomb-making materials to terrorists worldwide, but I said, 'Hey, I'm not a terrorist.'"
Young continued: "I deal with the broken homes. I deal with the children whose lives are up for grabs because someone is selfish enough to step outside the marriage and do what they want to do."
Biderman shot back in defense of his users.
"What I hear all the time is, 'Why cheat if it's not working for you, just leave.' That's the selfish act. Walking away from your family to pursue your own sexual needs, that's a sexual act," he said. "And so, what I hear from my members all the time is they're in sexless relationships, they've tried talking about it. And so rather than leave, they would rather do this. If you can't understand people in those positions, I don't really know what kind of pastor you are because they are suffering."
As the debate continued, Daugherty spoke up regarding the role God plays in marriage, adultery and divorce.
"I'll say, too, that we have to remember that God didn't mess up the institution of marriage. God created it perfectly. So whenever we're talking about kind of revisiting marriage and these sorts of things, it's because, like Ed said, we dropped the ball on this," he said.
Block, who said she thinks adultery is a terrible thing, also isn't sold on the ideal of marriage.
"I don't think it's a bad idea," she said. "But I think the way we've designed it, this Cinderella fairy tale -- happily ever after -- that 40 percent of people fail at, and one out of three men cheat on, it doesn't work for everyone. It works for some people fabulously! Some of my very best friends are monogamists. But it doesn't work for everyone."
After almost two hours, and after the audience asked the panelists questions and discussed their own battles with adultery, the debate came to a close.
"We need to not be afraid to have these sorts of discussions," said Daugherty. "You know, sometimes I have to admit, in some of our Christian circles, we have a tendency to just kind of get in our little bubbles, our cocoons. And were unwilling to engage culture. Were unwilling to even entertain other ideas and notions, because were so afraid that if everybody doesnt agree with us, then everything is lost. Well folks, everybody is not going to agree with us. And that's OK. But lets be open enough to be able to have conversations and dialogue so that we are not intolerant of other people."
"Really thoughtful questions and I couldnt have asked for more, so thank you for hosting us," said Biderman. "Again, I think I agree with my friends over here, that its our choice [to be monogomous]. I've chosen for myself to be in a monogamous relationship. But I know that it's about my effort and nothing else. And if it went wrong it would be my fault."
Young then closed the debate with a prayer, praising his fellow panelists, and asking God to bless the lives of both Block and Biderman.
Click here to watch the full debate