Polyamory: The New Monogamy?

Boy meets girl.  Girl learns that Boy already has girlfriend/wife.  Girl and Boy get together anyway.

Girlfriend/wife learns about New Girl.  Girlfriend/wife stays with Boy.  New Girl stays with Boy too.  Now Boy has Girlfriend/wife and New Girl.  Is this cheating?

Traditional claims will say: Boy is a dog.  Girlfriend/wife is stupid.  New Girl is a homewreckin' ho!

But what if this scenario is more common or just as prevalent as good old fashioned one man-one woman "monogamous" relationships?  What if more people are knowingly but quietly sharing partners?

If so, what sort or people do this?  What are the "rules of engagement" that make such seemingly complex "threesomes" less complicated?

Only those that engage in such bonds would really know.  I can say that these polyamorous relationships differ quite a bit from Swinging, which is based purely on sexual intrigue.  Mutually consenting, polyamorous relationships are creeping into mainstream circles discreetly with similar dynamics of traditional relationships.  This means that more and more people are somehow coming to terms with their own presently unique or non-traditional ideas on what love, faithfulness and compatibility means.

Of course I suspect that men would be more accepting of the "poly" union as long as they do not have to share women.  I also suspect that most women would openly say they would never choose to willingly share a man with another woman.  But people say the lots of things, right?

But what do people actually do?

More than half of marriages end in divorce.  Aside from money, infidelity is a top reason for separations and divorces.  A February 2012 article via the Washington Post cited: "In a 1991 study, sex researcher Shere Hite found that 70 percent of married women have cheated on their partners; a 1993 follow-up study found that 72 percent of married men have as well. According to a 2004 University of Chicago study, 25 percent of married men have had at least one extramarital affair. And with more than 12 million members looking for extramarital intimacy on Web site AshleyMadison.com (tagline: “Life is short. Have an affair.”), it’s easier than ever to break marriage vows. A wedding ring is not insurance against cheating."

The fact is, more than half or married people cheat.  People have different reasons for cheating in traditional marriages but what if they did not have to cheat?

A close friend of mine is married to a woman that is open to sharing him under very specific conditions.  He met another woman who was interested in having an affair.  But when he told the woman that he didn't really have to cheat because his wife was open to sharing, the woman opted not to deal with him.  He offered me this insight on the possible reasons why the other woman did not engage the situation:

1. The Other woman felt safer being a secret because secrets have power.
2. The Other woman probably wanted more than an affair.
3. The Other woman was intimidated by the wife.
4. The Other woman could not leverage the affair against the husband.
5. The Other woman did not want another woman to know she was open to sharing willingly.
6. Secret affairs are the norm in the minds of people that believe in traditional unions- anything else is too risky or unusual.  

It's funny to me how willing lots of woman are to engage married or attached men, especially if they can remain separate or a secret from the wife/girlfriend.  But I wonder if there would be less drama and healthier relationships if people just shared openly under their own specific rules of engagement?