"Women set the rules," said Nicole Cray of Behind Closed Doors. "Men can talk about what they want but women make the decision about what they want to do and don't want to do."
And women aren't just setting the rules, they are driving the explosive growth of the swinger culture on the Internet.
Five years ago, AdultFriendFinder.com, a website that helps swinging couples connect with other couples for a monthly fee, had 5.4 million swinger subscribers worldwide, and now the company said they have more than 10 million. Ryan Hunt, the community manager for the website, said the majority of the traffic to the site is coming from women.
"This is a new generation of swingers," Hunt said. "Usually people get into swinging between 35 and 50+ but we've seen people who are now more comfortable with being online and having kind of a more sex-positive attitude towards things that want to explore swinging at a younger age."
Another website, AshleyMadison.com, lists 14 million people in 22 countries who are looking to have extra-marital hook-ups. Behind Closed Doors also has a website, SchoolofSex.net, that serves as a social network for members to meet each other online.
But there is a reason why the Bible includes a commandment against coveting thy neighbor's wife -- we might be biologically hard-wired to have several sexual partners. Helen Fischer, an anthropologist who has studied sex and adultery for years, said she has lived in 42 countries and there is "not a culture in the world that is not adulterous."
"We are predisposed to eat meat. We are predisposed to fear when an animal is running towards us and we probably are predisposed towards adultery," she said.
Another couple who attended the Behind Closed Doors event was Cassie and Mike from Bristol, R.I. They have been married for four years, both have kids and successful careers -- Cassie runs a hair salon and Mike is a solutions engineer. They look like your next-door neighbors, but they spend the evening scoping out the room for strangers that seem approachable for sex.
"I think the best way to describe [swinging] is 'dating as a couple,'" Mike said. "We find it erotic to go out and meet people that have similar interests and similar sexuality."
"Just makes it hot," Cassie said. "Swinging is not love. I'm in love with my husband and it just enhances out sex collectively afterwards."
"There's a lot of branches on the swinging tree, so you have to figure out which branch do you swing from," she added.