Only a handful of mammal species on this planet are monogamous – and we're not among them. So is it time we grew up about sex? Suzanne Harrington reports
Richard and Mary have been together more than 20 years. They have sex often, never argue, and adore each other's company.
Their relationship is harmonious, loving, intimate and balanced between the needs of themselves as a couple and the needs of the family (they have three children together).
They have always been sexually and emotionally monogamous, and say that their relationship gets better as time passes.
Richard and Mary sound like they are made up, but they're not – they are old friends of mine.
I have changed their names, but the quality of their relationship, where both partners tick the 'very happy' box in all aspects of it, is definitely something of a rarity.
They remain monogamous because they are crazy about each other, not because of fear, duty, habit, children, financial constraint, co-dependency, inertia or the unspoken assumption that all humans, once paired off, are hard wired for monogamy.
Newsflash – we're not.
David Barash and Judith Eve Lipton's book 'The Myth of Monogamy' examines how monogamy is not automatic, either for human or non-humans – only a handful of the approximate 4,000 species of mammals on the planet (including us) form anything resembling life-long pair bonds.
Professor Roger Rubin, an American academic specialising in family relationships, has identified just 43 out of 238 human societies around the world which are monogamous. This is because monogamy is not in our nature.
It is, however, very firmly in our culture.
Psychologist Meg Barker, in her book 'Rewriting The Rules', summarises the traditional rules of monogamy as follows.
A: It is an unspoken assumption that each half of the couple will be sexually and emotionally exclusive within the relationship.
B: If you break the monogamy, it is considered very wrong, and the relationship will mostly likely end.
C: Monogamy is your only option.
This is all very well if it works, but what about the rest of us?
Referring to a 2004 US study, Barker writes: "As many as 60pc of men and 50pc of women have had sex with someone other than their spouse when married."
These figures would not suggest that human beings are pre- programmed, like swans, to mate for life, yet "the discovery of an affair often makes the end of a relationship, or at least causes considerable unhappiness amongst all concerned," Barker adds.
And here's the bit that doesn't make sense: it is more of a social stigma to admit to consensual recreational sex with your partner's knowledge and participation than to admit to an illicit affair.
"Clinging on to existing rules has led to a culture which holds up being 'normal' as more important than almost anything else," writes Barker.
"It is certainly the norm to claim monogamy, but whether it is the norm to be monogamous is another thing."
She continues: "People living close to a swingers' club recently organised a petition to have it closed down because they found it offensive.
"The owner commented this was ironic because it was a well-known 'secret' that several of the local community were having affairs with each other's spouses. This was seen as acceptable, because it was kept hidden."
This reflects the bigger social picture, which social scientist Catherine Hakim calls the "puritan culture" of Britain, Ireland and the US.
Hakim believes that we need to acknowledge our sexual drive as a normal part of human behaviour.
In 'The New Rules of Marriage: Internet Dating, Playfairs and Erotic Power', she argues that our insistence on monogamy can turn marriage into a prison, and that we need to loosen up.
According to Hakim's research, one-fifth of all US and UK marriages are sexless, yet we persist in labelling affairs as 'cheating', whereas she believes that no-strings sexual liaisons preserve the primary relationship because the person seeking sexual contact outside the relationship is taking responsibility for their own needs, rather than breaking the relationship up.
She advocates a kind of don't-ask-don't-tell policy, where we are grown-up about our sexual needs, and can meet them via adult dating sites.
Her argument is that we need to stop calling this behaviour 'cheating' and realise it is just sex. No biggie.
But deception in a committed relationship does seem like a biggie, doesn't it? It involves messing with fundamentals such as trust and truth, yet why accept unwanted celibacy in the name of something called monogamy?
Could there be other options?
"We've been playing with other couples for a few years now," says David, who is married to Jane (not their real names) and has two teenage children.
"We go to fetish parties, Jane dresses up in fantasy gear and we play with others in a safe, comfortable environment. It's really exciting," he explains.
"It's our secret, and we have loads of friends in that scene now, but our 'normal' friends don't know about it."
David and Jane don't have penetrative sex with other people, but instead enjoy fetish role play. This aspect of their private life is arranged online, as is Sarah and Ian's, who are swingers.
Sarah and Ian regularly go to a small handful of private swingers' parties. They arrive at the parties together, socialise for a while, then pair off with others and have sex, before leaving together a few hours later.
"It's a long way from the car keys in the bowl, 1970s image of swingers," says Sarah.
"I would never have sex with someone unless I found them attractive. I really enjoy it, and I really like that Ian is having fun too. We are open about it to each other, and so there's no jealousy. We know we are never going home with anyone else except each other."
What is striking about these two couples is the quality of intimacy and balance within their relationships. They are grown-up about recreational sex and seek it out in appropriate places.
But what if you're not? And what if your partner is gagging for it?
Should men and women equally turn a blind eye to their partners having no-strings sex with others?
"I would hate it," says Sarah. "So would Ian. The whole adventure of our sex life is that it's shared and that we're not secretive. I could have sex with men in front of him, but never behind his back."
Julie and Tony have been living together for four years. When he went to South America for a few months, Julie told him she did not expect him to remain celibate during his time away; all she asked was that he had safe sex, and that he never had sex with the same person more than once.
He complied. He did not, however, reciprocate by offering Julie her own hall pass, saying that it would drive him insane thinking of her having sex with other men in his absence. She also complied.
Did it work for them? Well, they're still together, still in love, and planning babies.
Does she silently resent him for not remaining sexually monogamous when he was away?
"No," she says. "Sex is sex. If he'd been writing anyone love poems, it would have been different."
And the double standard? She shrugs. "If it had been longer than a few months I would have insisted," she says. "As it was, I didn't mind one way or the other. What matters is we're open with each other."
Interestingly, men put a greater emphasis on sexual monogamy, while a quick and highly unscientific straw poll on Twitter confirms what we already know – that women greatly value emotional monogamy.
In other words, if your long-term partner had one-off sex with a stranger, would it bother you more than if he stayed up all night bonding emotionally with a woman who was not you?
Whereas generally speaking, heterosexual men tend to react badly to their partners doing anything physical with another man.
Either way, the result – feelings of rejection, broken trust, insecurity – is not ideal. Yet we emphasise monogamy over trust and emotional intimacy.
Polyamory – that is, more than one lover in the course of a long-term relationship – may be a healthier option over sexual monogamy.
What matters is not how many lovers you have, but how you handle it. What matters is love and trust and communication.
Recently, scientists have shown how spraying the bonding hormone oxytocin up the noses of men in committed relationships meant that they felt less inclined to think sexual thoughts about women who were not their partners. But do we really have to neuter ourselves like this?
This is not about encouraging bad behaviour – lying to each other about sex is hardly original – but to look at our options. Monogamy is negotiable. We are grown-ups.