-- On the hit ABC show "Desperate Housewives," cheating destroys marriages because spouses lie and get caught.
But we found couples who say they have found a way to enjoy the company of others without the deception. It's called the "lifestyle," or swinging, an arrangement in which couples have sex with other couples, and there is no secrecy.
Brian and Olga Depenbrock got married four years ago. Now they run a business together, and after work they like to go to a club in Fort Lauderdale, Fla., called Trapeze, which also has branches in Atlanta and Philadelphia.Trapeze looks like other nightclubs, with a dance floor, buffet, bar.
But it's not like other clubs, because in back there's a locker room where couples can get undressed and, if they want, have sex in different bedrooms with other couples -- or watch one another in hot tubs. It's called swinging or the "lifestyle."
Isn't it immoral? Four couples I talked to said no, it's a good thing.
"What we do is not illegal. And I don't believe it's immoral," said Brian.
Chris, who takes part in the lifestyle with his wife, Lavonne, said, "I don't want to be 85 years old, looking back on my life, like, 'Man, I didn't have enough sex in my life.' " Like most of the couples we talked to, Chris and Lavonne didn't want their last names used.
Another swinging couple, Bob and Tess, were college sweethearts. They've been married 19 years, and five years into their marriage they decided to try the lifestyle.
"Tess was the first woman I ever kissed in my whole life. So you always have an innate curiosity about 'How would another woman feel?' I no longer have that curiosity," Bob said.
Swinging was Tess' idea. She heard about it from a girlfriend and was intrigued. She figured their relationship was strong enough to give swinging a try. "You have to be completely open and honest with each other," she said.
Won't they look back at their lives and feel that they ruined the intimacy they had with each other by having sex with all these other people?
"No. It's made us much stronger over the years," said Bob. "Just 'cause we are attracted to other people, doesn't mean that we don't love each other."
But if they really loved each other, they wouldn't be attracted to other people, right?
Bob and Tess don't believe that. "To us, sex is not love. Sex is sex. It's just natural to be attracted to people, to other people. I mean, that's just nature. And we decided one day not to suppress nature," Bob said.
The first time Bob and Tess went to a club, they didn't participate. They just watched. That's common. Often almost half of the people at the clubs are "soft swingers" -- they just watch, without having intercourse, according to the club owners and swingers we met.
But watching had an impact on Bob and Tess at home. "We had the greatest sex of our lives that weekend," Bob said.
"Hard swinging" is group sex. The couples we talked with weren't concerned about catching diseases. They said everyone in the group uses condoms.
They also said they were surprised to meet other "nice people" at the clubs.
"Our eye-opening experience, was 'wow, there are actually other people like us,' " Bob said.
Apparently, there are a lot of them. About 4 million people are "swingers," according to estimates by the Kinsey Institute and other researchers.
Swingers have become a multimillion-dollar travel industry, so be careful when you pick a family vacation spot. (Watch out for code words like "clothing optional," "adult fun" and "couples only.") Hundreds of resorts now cater to the lifestyle. There are also swingers' conventions that take over entire resorts. Inside, thousands of couples play out sexual fantasies.
"It's a worldwide phenomenon," according to award-winning journalist Terry Gould.
When Gould was assigned to write a news story about swinging, he assumed it would be all sleaze. He was surprised when he went to an elegant club.
"I met bankers and lawyers, and I started talking to these people," he said.
Gould then spent three years researching the lifestyle and the people who swing.
"Most of them don't drink and most of them don't use drugs. They believe in raising children in clean-cut, stable environments. They match our paradigm of the sunny suburbanite," he said.
In his book "The Lifestyle: A Look at the Erotic Rites of Swingers," Gould concluded couples swing in order to not cheat on their partners.
"They see it as consensual, co-marital sex and something that they're doing in order to spice up their own relationships. They are not going to a swing club to have sex with other people. They're going there to get hot for each other," Gould said.
Chris and Lavonne are new to the lifestyle. They've been married five years, and about a year ago decided they wanted to experiment. They checked out Web sites where thousands of people seeking strangers to have sex with can find one another.
Brian and his wife run such a site, and it's very popular. "We have a half million members. We have 70,000 per day that visit," he said.
I would think men might pressure their wives into swapping. But the women say they're the ones who are in charge.
"The women are the ones that make this happen," Tess said.
"We have the veto right," Lavonne said. "So if we are not attracted to the other couple, it's not gonna happen."
"It's usually men that bring women into the lifestyle. But it's the women that keep 'em in the lifestyle," Bob said.
The women say they find the sexual freedom liberating.
"It definitely changes women. And it makes women more confident -- that they are the ones in charge," Tess said.
The couples set up certain rules beforehand. Some couples don't do anything without the other. Some couples don't kiss others.
But don't the couples worry that their spouse will find they like someone else better? Those I talked to said no.
"People in the swinging community swing for a reason. They don't swing to go out and find a new wife," Chris said.
They're so happy and unashamed of their swinging, they let us tape them. But that brings up a question: Do their kids know?
"I don't tell my kids about my financial issues, and I don't tell them about the sexual experiences I have with Chris," said Lavonne.
Another swinging couple, Mary and Ray, have been married for five years. Their kids, from previous marriages, are 18 and 21. They said the 21-year-old son knows about their lifestyle, and they say he thinks it's just fine.
We spoke to a dozen marriage counselors about the lifestyle, and not one of them said don't do it. Most said consenting adults will do what consenting adults do. But they also said getting sexual thrills outside of marriage can threaten a marriage.
"There is a tremendous appeal about the idea of swinging. ... But to sustain swinging as a lifestyle, it's going to pull at the fabric and the foundation of the marriage. And that foundation is being faithful, that's what standing up on the altar is all about," said Dr. Scott Haltzman, a psychiatrist who specializes in marriage and couples counseling.
But the swingers say they aren't cheating. "We all go home with our spouses. We're not living a lie," said Lavonne.
The swingers claim their marriages are stronger because they don't have affairs and they don't lie to each other. It's all out in the open.
"People need desires fulfilled. But I'm going home with [Chris] no matter who I enjoy. I love him. I have my life with him," said Lavonne.
Bob said the swinging has deepened his love for Tess. "I feel more love for her now, knowing what it is like to be with other people than I think I would have if that's the only experience I have ever had in my life."
This story originally aired on "20/20" on March 18, 2005.