From virtually the moment we're born,
there's a story that's preached across cultures and continents.
It's a familiar fairy tale.
[narrator] She was even more beautiful than he had thought.
That finding one true love is the key to a fulfilled and happy life.
I've been doing a lot of thinking, and the thing is...
-I love you. -I love you.
Ditto.
As an adult, we're forced to reconcile the messaging on monogamy
with one simple fact.
Humans are terrible at it.
It's kept Jerry Springer on the air for 25 years.
[crowd booing]
I've been sleeping with Eddie.
-You cheated on me with her? -I have your name tattooed on me!
-Why would you sleep with him? -How many girls did you take?
In 2016, 2.2 million U.S. couples got married,
but over 800,000 called it quits.
Our quest for and failure at monogamy has caused so much pain and heartbreak.
If it's so hard for humans to be monogamous,
why do most of us all around the world
make it one of the most central goals of our lives?
[woman] I start asking myself, "Is he right for me?"
[reporter] Belgium's King Baudouin married Doña Fabiola...
I think I am a very lucky man.
[reporter] A beautiful shot of the new royal couple.
[reporter] Wonderful.
The Prince of Wales has admitted publicly that he was unfaithful.
I'm announcing my resignation.
[reporters] The crime was to have conceived a child with a married neighbor.
Nelson Mandela... a broken marriage.
I did not have sexual relations with that woman.
If you ask couples why they chose monogamy,
you'll hear one answer again and again.
They fell in love.
We met, in a candy store.
1946.
We went to college together.
We were both in a relationship.
And... we didn't cheat.
You look so guilty every time we talk about this.
I am bad at talking about this.
It's arranged marriage.
Whatever they selected for me, it was good.
And I'm very happy with that.
We had a study date one night
and that study break turned into anatomy, I guess.
I never felt this way about anybody before.
I feel God has blessed us.
We found true love.
Of course we did. We're still here 70 years, what do you expect?
25 years, I would have got out on good behavior.
I would like to think that soulmates are real, but...
She's my soulmate.
Well, you're mine too.
But monogamy and love aren't the same thing.
We are so psychotically welded to this idea...
that monogamy means love and love means monogamy.
In the absence of monogamy, there is not love.
Love is a feeling. Monogamy is a rule.
You'll only have sex with this one person. And most people live in a culture
where they're expected at some point
to make that rule a legal contract, called marriage.
In many countries, breaking that rule is a crime.
In the U.S., adultery is illegal in at least 20 states,
and although they're rarely enforced,
punishments can range from a $10 fine to three years in prison.
If you are in a monogamous relationship for 50 years
and you fell down once, you cheated once,
the whole relationship was a lie and a failure.
Most human beings have ambivalent impulses
that it's nice to have someone you can rely on
but there's also the temptation of novelty.
Why would humans all around the world invent a rule
that's so difficult to follow
and treat breaking it as such an enormous betrayal?
[narrator] Should a male have on his clothing so much as a strand of hair
from a female not his wife, a serious crisis may result.
For more than a century, there's been a culturally accepted explanation.
Sound check.
One. One. One. One. One. One. One.
The standard narrative is the story that everybody knows. That men want to be free sexually and spread their seed around the world
and women want to be very exclusive and particular and choose a provider,
because they're vulnerable and the children need to be taken care of.
Women trade sexual fidelity to men
in exchange for goods and services, essentially.
In this narrative,
there's another reason why men wouldn't want women to sleep around.
If a baby comes out of a woman's body,
there's no question but that she is genetically related to that baby.
The male has to take the woman's word for it.
Biologists have known for a very long time that...
men are far more inclined to seek multiple sexual partners.
And the reason for that is really quite clear.
[educator] Now in the first place, remember that the male sperm cells
are being produced all the time,
while only one egg cell is produced each month.
There's very good, and I don't mean ethically good, but very understandable
evolutionary payoff for males as being randy bastards.
[inaudible]
But there's one big issue with that explanation
of promiscuous, possessive men and demure women.
At lots of points in time, in places in the world, people didn't follow it.
Anatomically modern human beings
have existed for at least 300,000 years.
And for more than 90 percent of that time, we lived as hunter-gatherers.
Anthropologists refer to them as fiercely egalitarian.
There's no reason to think that our ancestors shared everything
except sexual partners.
Of course, we can't go back and interview our foraging ancestors,
but we have the accounts of explorers and Europeans
who first developed and saw these societies
before they'd been much touched by outsiders.
And they are surprised and shocked at the difference in sexual mores.
There's a wonderful story that a Jesuit
who lived with the Naskapi Indians for some time, and he would ask,
"If you let your wives have this much freedom,
how do you know that the child she bears will belong to you?"
And he recorded the answer of the Indian:
If a child is crying and the adult nearest to that child picks it up,
nobody says, "Hey, hey. Your kid's crying."
No, it's...
there's a commonality to parenthood among hunter-gatherers.
One of those groups are the Bari of Venezuela,
where every man who sleeps with a woman while she's pregnant
is considered a father of the child and helps provide for it.
Now in our society, that would probably not work very well.
I'm not recommending it.
But in that society,
the child who had several fathers named because she'd slept with several fathers
actually had a much better chance of surviving to adulthood
because those men contributed.
Did you ever think of going with somebody else after you married me?
What, are you crazy?
We don't like to say we're open. We like to say we're slightly ajar.
Exactly.
That's not good in my way.
In our language, also, they say, "Pati parmeshwar."
That means "Husband is like God".
-This is our culture. -Our culture.
We actually kind of met through the non-monogamy "community".
I define this relationship as this is my cohabitating partner
-and we call each other otters. -Yeah.
We are primary partners and our other partners are secondary partners.
I find it really fascinating.
I think about it a lot, like if I could ever do that, but I don't know if I could.
I had a threesome with, like, two friends of mine that I initiated.
I decided that it would be cool to experiment with multiple people
with somebody I really loved and cared about.
The queer community is berated with the idea that our relationships are lesser
and that they're actually not up to par in the hetero-normative standard.
And all of that is bull.
We shouldn't be surprised that some cultures practice non-monogamy.
Because in the animal world, true sexual monogamy is virtually unheard of.
The most romantic creature might be the Diplozoon paradoxum,
a parasitic tapeworm that literally fuses together with its partner for life.
But humans aren't tapeworms or apes,
and our closest relatives in the animal world are chimps and bonobos.
[Christopher Ryan] We're closer related to chimps and bonobos
than the Indian elephant is to the African elephant.
[narrator] The close comparison exists in bone and muscle structure,
and in the capability of responding to stimuli and solving problems.
Clearly, chimps and bonobos are anything but monogamous.
Bonobos have sex at the drop of a hat.
[song] I know... that I just met you...
They have sex to say hello, they have sex to say goodbye.
They have sex when they're stressed out.
For both male and female bonobos,
that free love philosophy makes evolutionary sense.
The males get to spread their seed
and the females get to take in the seed of multiple males,
which then compete against each other to fertilize her egg.
It's survival of the fittest, for sperm.
There are aspects of bonobo anatomy that seem adapted to promiscuity,
and intriguingly, you can also find a lot of them in humans,
suggesting we may have evolved to be non-monogamous, too.
There's body dimorphism.
In species that are more promiscuous,
the males tend to be 15 to 25 percent larger than the females.
And in theory, if there are males battling to impregnate women,
testicles would be bigger and stronger.
[Christopher Ryan] Human testicles are intermediate between very large testicles
in bonobos and chimpanzees, and very small testicles in gorillas, for example.
There's the human penis,
tied for the biggest among all primates, which has a unique shape.
We have this much thicker penis with the flared head.
This shape creates a vacuum in the female's reproductive tract
that tends to pull any sperm already there and pulls it down away from the ovum,
thereby giving an advantage to the sperm of the man who's having sex at the moment.
There's also female copulatory vocalization,
a phenomenon so well-known and accepted,
it's a standard feature of movie sex scenes.
[groaning and screaming]
What we see is that female copulatory vocalization is common
among primates that engage in sperm competition.
Then there's the fact that humans and bonobos have sex to bond.
And not just to have children.
Which might explain the way we face each other during intercourse.
You see humans and bonobos are the only two that face each other while having sex.
And why we have a lot more of it than most mammals.
So, clearly when people say
so-and-so had sex like an animal, they're getting it backwards.
And there's now a lot of evidence that monogamy is a more recent invention
than most of us would expect.
Around 12,000 years ago,
when most humans stopped being hunter-gatherers
and figured out how to farm.
You get a very overpowering concern with property rights.
As the Greeks put it, you don't want a foreign seed introduced into your soil.
For thousands of years, marriage was the way to increase your family labor force.
You made peace treaties, business alliances...
The more I've studied, the more I became convinced that marriage was invented
not to do with the individual relationship with a man and a woman
but to get in-laws.
You know, and it's amusing because today we see in-laws as the big threat
to the solidarity of the man and the woman.
But that's what marriage was about.
You look back at Anthony and Cleopatra, that was not a love story at all.
That was two people from the most powerful empires in the world
trying to figure out how they could get together and rule both of those empires.
The idea of marrying someone for love,
Coontz says Western societies only started doing that a few hundred years ago.
As we made a transition to the idea that marriage should be on the basis of love,
it scared people.
Defenders of traditional marriage said, "Oh, my gosh.
How will we get a woman to marry at all if she says, 'Eww, I don't love him.'
How will we stop people from getting divorced?"
So a new idea took hold.
Men and women needed to find love and marry
because they were two parts of a whole.
Men were aggressive and protective,
women were nurturing and demure.
They were opposites who completed each other.
The field of evolutionary biology also developed around this time,
pioneered by male scientists
who used theories on sexual selection to explain Victorian gender roles.
As Charles Darwin wrote in The Descent of Man:
And it's possible his ideas became so popular
and survived so long because it made sense to us
in the societies we were living in.
But if monogamy is all a made-up construct,
a way to enforce gender roles and social order,
how do we explain that visceral, deep-rooted feeling we get
when our loved ones stray?
Tell me something. Are you the jealous type?
I feel like we don't really deal too much with jealousy.
I... I don't know why that is.
-What it is... -It's because we're sluts.
-To be honest. -I don't get, like, jealous like that.
It's important to understand why you're feeling jealous because jealousy is not--
It's not a feeling, it's usually rooted in some other sort of thing.
It's not a descending guillotine. It's like jealousy is an event.
What's the best way to deal with that event?
Who were you really with? That little blonde secretary from the office?
I don't think you'll ever find any society where there was no sexual jealousy,
but we also have these other kinds of impulses of generosity
and of a sense that maybe there are other parts of the person
that are more important than the sexual person.
And these coexist and they battle and I think they will always battle.
I say monogam-ish to describe my relationship with my husband.
We've been together for 24 years, and not monogamous for 20 of those years.
And I've had people look at me and say, "I could never do what you guys do
because I value commitment too highly.
All three of my marriages were monogamous."
This person was committed to monogamy, not to any of the people they married,
they were committed to monogamy.
Non-monogamy is getting more mainstream attention.
-Define polyamorous. -Without monogamy.
-Polyamory... -Polyamory...
-Polyamorous. -It's called polyamory.
-Polyamorous people. -Threeple.
-Non-monogamous, okay? -You couldn't be.
A 2016 study found one in five Americans
have been in a non-monogamous relationship at some point.
And in another survey, a third of Americans said their ideal relationship
would be non-monogamous.
Monogamy as we know it has been through many incarnations.
It's been forced.
It's been useful.
It's been beautiful.
It's been subverted.
As human society evolves,
so will human sexuality.
As we enter what I think of as uncharted territory,
for the first time in human history,
we're trying to develop relationships that are not based on coercion.
Coercion of women by their economic and legal dependence,
coercion of women by their bodies,
coercion of men by the social and economic structures.
We're trying, I think, to find maybe a new balance.
Monogamy isn't natural.
It means we have to recognize that, because it's not natural,
it's something that we're going to have to work for if we want it.
One of the things that I think makes human beings particularly interesting,
and maybe even unique in the animal world,
is that we're capable of doing things that are unnatural.
Monogamy is like vegetarianism.
You can choose to be a vegetarian and that can be healthy.
It can be ethical, it can be a wonderful decision,
but because you've chosen to be a vegetarian
doesn't mean that bacon stops smelling good.
If we're lucky,
it's no longer about what kinds of relationships we should have
in the modern world.
It's about designing the kinds of relationships we want to have.
Humans may not have evolved to be sexually monogamous,