"[It] demands knowing yourself, replacing guilt with acceptance, communicating and embracing sexual energy, spirituality, new beliefs and a new culture," she told ABCNews.com. "Overcoming jealousy is key."
As a clinical psychologist, Kuriansky has seen some "dismal failures, even for the leading proponents."
"One wife left her poly husband, saying, 'I'm just a girl from Kansas. I finally realized I don't want my husband f**king other women.' A husband had a rude awakening when his wife added another man to their household and her bed, only to declare she wanted a sexual exclusivity with another man."
According to expert Deborah Anapol, polyamory has been accepted by many cultures. In Hawaii, where she lives today, there is even a word for the extra partner -- "punalua."
"We talk like we invented it, but it's been around a long time," said Anapol, who counsels couples and families, and is writing a new book on the topic, "Understanding Polyamory in the 21st Century."
But, she said, today's polys have little interest in legalizing marriage, and "the state being involved in their lives.
"Polys don't want to make it into a special identity and don't want to be known as a poly person," said Anapol. "They just want to live their lives. A movement tends to put you in an oppressed, underdog position."
"I'd like to think the movement has already succeeded and in the most liberal parts of this country, it's more accepted," she said. "The shift has already happened."
At 57, Anapol is now "single" after two marriages -- one traditional and the other polyamorous -- which produced two daughters.
"Both are comfortable with the idea," she said. "The 37-year-old has chosen a conventional monogamous marriage and the 20-year-old is still experimenting, but definitely attracted to the idea."
But Anapol, who has several long-term "intimate friendships," has discovered that being polyamorous "doesn't solve all marital problems."
As for Love and Cougar, who celebrate their 10th anniversary this month, they say their relationship is "extraordinary."
"We've been very cautious," said Love. "He likes to say he steals my boyfriends. I am not interested in men unless they are interested in me."
"Every person is seeking to find a fit that works for them," she said. "It's hard enough to find a monogamous partner. It's exponentially harder to fit the quirks of two people, plus a third person."