This echoes what many poly activists say, Aviram found. “They tell you they have an innate sense that they are wired this way. That this is a natural way of being for them.” If that is the case, these groups should receive special anti-discriminatory protection under law as well, she says.
However, even poly people say it is not clear cut. In small 2005 survey Meg-John Barker of the Open University in the UK, asked 30 polyamorous people how they identify to find that about half saw it as “a fairly fixed identity”, while the other half saw as a choice, as “an ethical alternative to infidelity”. Eve and Franklin also suggest it can be a bit of both.
That some people choose polyamory in order not to cheat on their partner brings to light a striking contradiction about monogamy in the west: adultery is rife. Pallotta-Chiarolli points out the irony that mainstream media almost accept affairs as a social norm. “But when it comes to ethical non-monogamous relationships… this is considered [abnormal].”
Aside from that, most people are not monogamous in the true sense of the word: staying with one partner for life. You only need to look at divorce rates to see that about one-third of us practice what is referred to as “serial monogamy”, where we change partners over time.
Monogamy is also extremely rare in the animal kingdom, as BBC Earth explored in detail. Even among apparently monogamous animals there are many “extra-pair copulations”, or cheating. Our closest relatives, chimpanzees, bonobos and even orangutans all live in highly promiscuous societies, which suggests our common ancestor with chimps did so too.
In this view, “the idea that monogamy is ‘natural’ or ‘normal’ in human beings is hard to sustain”, says Barker. “As with so many things, there is a lot of diversity in this area.”
This all points the fact that just as there’s not one set way for love between individuals to be expressed. What works for one person or society may not work for another.
Relationships are eclectic and diverse, and while legal recognition for polyamory may be a long way off, with greater awareness of our differences, love in all its many forms is surely set to change.
This story is part of our Sexual Revolutions series on our evolving understanding of sex and gender.
Melissa Hogenboom is BBC Earth's feature writer. She is @melissasuzanneh on Twitter. Olivia Howitt is BBC Future’s picture editor. She Tweets as @OliviaHowitt.
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