From the outside, the resort looks just like any other along the sun-soaked beaches of Los Cabos, Mexico: pools and bars and volleyball. But before long, it's easy to see signs that this place is different. In the gift shop, not far from the sun block, were boxes of Viagra. Get the Full Story: Watch "Nightline" Tonight, Dec. 8, 2006, on ABC. Outside by the pool were big red beds, draped with wispy curtains. And these beds were not for tanning. It was very quickly clear that at this clothing-optional resort, most enjoyed that option. Nudity was the norm. After all, this was Desire, the second-best-known "swingers" resort on the planet.

Vacationers are known to have open sex on the poolside daybeds scattered around the Desire swingers resort. (ABC )

Banking on a Demand for Something Different

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.

These couples say participating in "swinging" parties, where they sometimes swap sexual partners, strengthens their marriages. (ABC News)

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 ...

Q: I am a 22-year-old woman, generally happy, but I have a problem with cheating. My peers seem to have no problems staying faithful, but I do. I have never been faithful to anyone, and I have had many relationships with men and women. Some found out, some didn't. I have finally found someone I feel like I can spend the rest of my life with. I am happy with him on every level, but I still cheat. I have been told this could be sociopathic, but I'm not sure. I have always really loved sex, all kinds, and have done everything short of urine, feces or anything illegal. I don't have any guilt, but I don't want my boyfriend to find out and leave me, or worse, stay with me as I continue to break his heart through constant cheating. Would therapy help? I hope you have some advice. I just wish I could stop. —She Kraves Acrobatic Nookie Konstantly

A: Why stop, SKANK?

You say it's not the skanking around that's making you unhappy — you enjoy the sex, you enjoy multiple partners, you enjoy everything short of urine/feces/criminal. If you're telling the truth — if you're not glossing over some deep-seated pain — the sex isn't the problem. What's troubling you is the deceit. You're worried that this boy, like the boys and girls before him, will be hurt when he finds out you're a lying, cheating skank.

But you can be a skank — and I'm using the term in the sex-positive sense — without lying or cheating. Have you tried being honest with potential boyfriends and girlfriends about your tastes and track record? Where there are no lies of commission or omission, SKANK, there's no deceit. And where there's no deceit, there are no boys whose hearts are broken when they find out they are being cheated on. Let prospective partners know who you are and what you're about before things get serious, SKANK, and your problem will be solved — i.e., boys and girls who want monogamy won't get involved with you. You'll encounter some rejection, sure, but if you keep the honesty thing up, sooner or later you'll find a partner who doesn't mind or thoroughly enjoys being cheated on. Ta-da, everybody wins.

Now, my advice would conclude with the previous paragraph if it weren't for the last line of your letter: "I just wish I could stop." If that's how you truly feel, SKANK, then perhaps there is something pathological about your behavior. And here's a little more evidence that your sexual adventures may not be coming from a particularly healthy place: Someone like you, SKANK, surely knows that there are men and women out there — wannabe swingers, the polyamorous, the growing legions of cuckold fetishists — that would kill to be with a woman like you. The fact that you haven't sought out any of these people and have instead dated and deceived the monogamously inclined is revealing. And what it reveals isn't pretty: If you've avoided the swingers, the polyamorous and the cuckold fetishists, SKANK, and sought out only guys and girls that will be hurt by your actions, then you're not skanking around because you enjoy it. You're doing it to wound and drive off people who attempt to get close to you. And that's something you should definitely hash out with a shrink.