An open relationship is a type of romantic relationship between two people in which both agree that it’s OK to have sex with people outside of the relationship.
It’s a type of consensual non-monogamy (CNM), an umbrella term for relationships between two or more people in which all partners agree it’s OK for one or more of them to have romantic, emotional, and/or sexual relationships with more than one person.
What is consensual non-monogamy (CNM)?
An open relationship is one type of consensual non-monogamy (CNM), also called ethical non-monogamy.
CNM is defined by the explicit agreement between partners that having multiple partners is acceptable, usually with clear agreed-upon details about how that works.
Everyone in a CNM relationship is aware of the deal. The core requirement of CNM relationships is that all the people involved have freely consented to it. They’ve confirmed they’re OK with themselves and their partner(s) not being exclusive to them.
Monogamy, on the other hand, is a relationship between two people in which the partners agree to be exclusive to each other romantically and sexually.
CNM is not cheating
In a CNM relationship, everyone is aware of the agreement of non-monogamy and has consented to it ahead of time.
It’s very different from “infidelity” or “cheating,” in which one partner takes on one or more romantic or sexual partners outside the relationship without the knowledge or consent of their partner.
Types of consensual non-monogamy (CNM) relationships
There are several types of CNM you may have heard of.
Under the CNM umbrella, there are several distinct styles of relating:
- Open relationships: The definition of “open relationship” is fuzzy. However, sex researchers say it’s a non-monogamous relationship between two people. The focus is usually on maintaining the primary bond.
- Polyamory: Partners engage in multiple romantic and emotional relationships simultaneously with the knowledge and consent of everyone involved. Types of polyamory include hierarchical, hinge, and kitchen table polyamory.
- Swinging: Often involves established couples or single people engaging in sexual activities with other couples or individuals. It’s often not romantic and people often do it by attending swinging events. Couples who swing often stay romantically exclusive.
How common are open relationships?
About 3–7% of adults in North America are currently in a CNM relationship, and 20% have engaged in CNM at some point in their lives, according to research.
One study in single people found that 1 out of 6 people were interested in having a CNM relationship.
Why do people choose open relationships and CNM?
There are many different reasons why people have open relationships, but not much research out there about it so far, so more is needed.
One study looked into the reasons why people had sex with a secondary partner (not their main relationship).
The researchers found that people in consensually non-monogamous relationships listed several motivations for having sex with their primary vs. their secondary partner.
Pleasure was the top reason for both. Physical desire for the partner and experience seeking ranked highly for both, too.
Self-esteem boost and the thrill of the forbidden were more highly ranked reasons why people had sex with their secondary partners, while love and commitment and expression of feelings were top reasons with a primary partner.
Here’s a complete list of the reasons people in CNM relationships gave for having sex, from most to least common, and how they differed between partners:
| Reasons people had sex with their MAIN PARTNER | Reasons people had sex with a SECONDARY PARTNER |
| 1. Pleasure | 1. Pleasure |
| 2. Love and commitment | 2. They desired the partner physically |
| 3. They desired the partner physically | 3. Experience seeking |
| 4. Experience seeking | 4. Self-esteem boost |
| 5. Expression of feelings (like being sorry or thankful) | 5. Thrill of the forbidden |
| 6. Stress reduction | 6. Love and commitment |
| 7. Self-esteem boost | 7. Specific sex (like kink) |
| 8. Thrill of the forbidden | 8. Stress reduction |
| 9. Specific sex (like kink) | 9. To have sex with someone of another gender than their primary partner |
| 10. Duty or pressure | 10. Expression of feelings (like being sorry or thankful) |
| 11. To have a baby | 11. Duty or pressure |
| 12. Utilitarian reasons, like getting rid of a headache or keeping warm | 12. Utilitarian reasons, like getting rid of a headache or keeping warm |
| 13. To have sex with someone of another gender than their other partner(s) | 13. Social status |
| 14. Mate guarding, to keep the partner from having sex with others | 14. To get resources from the person, like money or a promotion |
| 15. Social status | 15. Mate guarding, to keep the partner from having sex with others |
| 16. To get resources from the person, like money or a promotion | 16. Revenge |
| 17. Revenge | 17. To have a baby |
Who has open and CNM relationships?
People who have CNM relationships tend to be:
- Men more than women
- Younger people
- Non-heterosexual people more than heterosexual
- People with high cognitive empathy, the ability to see things from someone else’s point of view
- Those who are less prone to jealousy
- People who are able to feel compersion for their partner — that’s a feeling of joy when their partner finds love or sexual satisfaction with someone else
Education level, religion, and income don’t have a big impact on whether people are into CNM relationships.
Research suggests that people who have CNM relationships tend to fall into two groups: those who can live with monogamy or CNM, and those who consistently choose CNM over monogamy.
Benefits of being in an open or CNM relationship
One review of studies on open relationships and CNMs found that people in CNMs tend to experience these benefits compared with people in monogamous relationships:
- Potentially greater relationship satisfaction: Having other partners may help people make up for things they need but aren’t getting from their primary relationship. But this is controversial. Other research has found there’s no difference between people in CNM and monogamous relationships.
- Greater sexual satisfaction: Due to the ability to seek out partners who fulfill various needs or interests that you might not have fulfilled with a single partner.
- Better understanding of your own sexuality: You may have a greater chance to explore what you like and don’t like.
- Development of empathy and communication skills: Some researchers have found that open relationships can help people grow in these important ways, likely related to the communication necessary to start and maintain a CNM relationship.
Common challenges people have in open and CNM relationships
Open relationships can be rewarding, but as with monogamous relationships, they can come with problems.
Because society is largely structured around monogamy, partners in CNM often face unique social and emotional challenges.
Jealousy
Some people might think jealousy would be a major obstacle for people in CNM and open relationships, but jealousy actually happens less often in CNM relationships compared with monogamous relationships.
When it happens, it can negatively affect relationship satisfaction. But people in CNM relationships often see jealously as manageable and even as an opportunity to feel compersion — that is, pleasure from their partner’s pleasure.
Social stigma against CNM
People in CNM relationships face stigma legally and culturally. In most Western cultures, multi-person marriages are illegal.
According to sex researchers, there are several common stereotypes, myths, and misunderstandings about CNM that aren’t backed by research.
These misconceptions include the idea that CNM leads to getting more sexually transmitted infections (STIs). But research shows the opposite — that people in CNM relationships tend to practice safe sex more often.
Another misconception is that CNMs are oppressive to women. This not inherently true of CNMs, in which mutual respect is the norm, but it can be true in some kinds of polygamous relationships. Read our article on the difference between polyamory and polygamy for an explainer.
Other myths include that people who engage in CNMs don’t love their partners, and that they result in jealousy that ultimately destroys relationships.
Actually, when people prioritize consent and communication, CNM relationships can be just as satisfying and long-lasting as traditional monogamous ones, researchers have found.
People in CNM relationships tend to have high levels of intimacy, trust, honesty, and relationship satisfaction, studies say.
Still, bias persists against people who practice open relationships and CNM.
The cultural preference for monogamous relationships over multi-person relationships is also called mononormativity, monocentrism, or compulsory monogamy.
It can lead to discrimination in many different ways, such as rights and legal recognition for CNM parents.
What attachment style do people in open relationships have?
It turns out that there’s no clear evidence to show there’s any connection between your attachment style and your interest in being in an open or CNM relationship.
One study found that people with avoidant attachment tend to have more willingness to have CNM relationships, and had more positive attitudes toward them.
But when it came to people who were actually in CNM relationships, the percentage of people with avoidant attachment was lower than among people in monogamous relationships.
Further reading
For a deeper understanding of open relationships, consensual non-monogamy, and related ideas, read these Relationship Smart articles:
- Polyamory: A Primer on Sharing a Partner
- How to Be Friends with Benefits: Laying the Ground Rules
- How to Practice Ethical Non-Monogamy: 5 Tips
- How to Talk About Sex with a Partner: Before, During, and After
Health and science writer and founder of Relationship Smart, Stephanie believes the world of our minds is real, important, and studyable, and that our social relationships are core to our well-being — much more than we give them credit for. She created Relationship Smart to explore the endless ways our relationships affect us, and to answer all your burning questions about them with scientific rigor and sensitivity.