Monogamy: Can a monogamous couple happily become non-monogamous? It's possible but not easy, experts say

Couple in bed on their phones
Can a monogamous couple become non-monogamous? Of course, they can - but do these couples survive and thrive? Photo credit: Getty Images

By Ian Kerner of CNN

Editor's note: Ian Kerner is a licensed marriage and family therapist, writer and contributor on the topic of relationships for CNN. His most recent book is a guide for couples, So Tell Me About the Last Time You Had Sex.

Can a monogamous couple become non-monogamous? Of course, they can - but do these couples survive and thrive? What are the pitfalls and what are the pleasures?

More and more I'm seeing couples in my practice of all ages who have always been in monogamous relationships but now are seriously thinking about opening up their relationships. They are young couples just starting out, couples with young kids and a mortgage, and empty nesters looking to find their wings.

The reasons for taking the leap vary. Often one or both partners may be feeling sexually dissatisfied in the primary relationship - it may be boredom, mismatched libidos or a desire to explore new horizons. Sometimes there's a hunger for the excitement and energy that comes when people first connect with someone new. It's also possible one or both partners don't believe in monogamy. For some couples, sex has always been an issue, even though the rest of the relationship works.

No matter the reason, interest in non-monogamy - participation in nonexclusive sexual relationships - is on the rise. In a 2020 study of 822 currently monogamous people by Kinsey Institute research fellow Justin Lehmiller, nearly one-third said that having an open relationship was their favourite sexual fantasy, and 80 percent wanted to act on it.

What happens if your relationship starts off as monogamous, and you or your partner change your mind? That doesn't have to doom your relationship, Lehmiller said. "Research suggests that relationship quality is actually quite similar in monogamous and consensually nonmonogamous relationships," he said. "Both relationship styles can work well - and both can fail, too."

I believe the key to successful non-monogamy is in one word: consensual. Known as ethical non-monogamy, this approach is different from monogamous relationships in which partners cheat on each other. An ethically non-monogamous relationship involves two people who identify as a couple but who are not committed to a traditional relationship, according to sexologist Yvonne Fulbright.

"They've given each other the opportunity to date or have sex with other people independently," said Fulbright, who is based in Iceland. "Often a key component in these relationships working out is that the other relationship is only sexual, not romantic or emotional. There's no deception about engaging in sex with others."

Some couples may find ethical non-monogamy easier than others. That includes those who have discussed the possibility of an open relationship from the beginning as well as LGBTQ couples. "In my experience, gay and queer couples have more ease with non-monogamy," New York-based sex therapist Dulcinea Alex Pitagora said.

"They've had to do more introspection and communication around their sexual or gender identity," Pitagora said. "This additional time spent understanding who they are, what they want, and learning how to communicate it dovetails very smoothly into communicating about non-monogamy."

Weighing the pros and cons of non-monogamy

For couples who choose to open their relationships ethically, there can be benefits. "Non-monogamy can be fulfilling and a catalyst for self-growth," Wisconsin-based sex therapist Madelyn Esposito said. "This self-growth can deepen understanding and desire for your primary partner as you have the space to explore yourself and your own sexual needs outside of relational confines."

In an open relationship there is often less pressure to have all your sexual needs met from your partner, Florida-based sex therapist Rachel Needle said. "And there is less pressure on you to meet all of your partner's sexual needs. This gives you the opportunity to enjoy sexual activity with your partner but do it without added tension or anxiety."

Sometimes the heat generated outside the bedroom even finds its way back into the primary relationship. "Many nonmonogamous folks find that partner variety revs up their libido, and that this transfers over into increased sex in the primary relationship," Lehmiller said. "Something else we've found in our research is that, beyond sex, these relationships can also mutually reinforce each other. Specifically, being more satisfied with a secondary partner actually predicts being more committed to the primary partner."

But making the leap into ethical non-monogamy isn't always easy for couples who have been historically monogamous. Often, one partner is "driving," and the other is a reluctant passenger going along for the ride. Sometimes a couple can't agree on what constitutes non-monogamy (casual sex with different people versus repeatedly seeing one person), or they can't agree on rules (posting a profile online, staying overnight, bringing someone home, no kissing).

One partner might be worried about the social stigma if others find out or just can't get beyond all the cultural messaging that idealises monogamy. Non-monogamy can trigger strong feelings such as jealousy and possessiveness. "Even bringing it up as a curiosity can feel threatening to some couples/partners," Fulbright said.

What should you consider if ethical non-monogamy is on your mind?

Do it for the right reasons

There are any number of positive motivators for couples to try non-monogamy, but what you don't want to do is rely on non-monogamy to slap a Band-Aid on existing problems. "Using non-monogamy to fix a relationship is as effective as having a baby to fix a relationship - it's a terrible idea," said Rebecca Sokoll, a psychotherapist in New York City. "You need a strong and healthy relationship to make the transition to non-monogamy."

Don't do it to distance yourself from your partner. "Ethical non-monogamy can also be a defence mechanism, a delay tactic, a hide-and-seek game and an aversion to closeness," said Minnesota-based psychotherapist Hanna Zipes Basel, who specialises in this area. "I see couples succeed when they enter non-monogamy with an already secure functioning relationship, when they are both equally desiring non-monogamy, and/or they have had prior experience or done their homework."

Educate yourself

"Get educated on the wide array of philosophies, structures and agreements that are possible in the ethical non-monogamy world through books, podcasts and articles," suggested sex therapist Sari Cooper, who directs the Center for Love and Sex in New York. "Journal about what each of you is looking for through this transition and discuss these goals with your partner to see if you're on the same page and, if not, what overlaps or compromises might work."

Talk, talk and talk some more

There's no doubt that ethical non-monogamy requires communication - and lots of it. "I suggest a 'what if' conversation before anyone takes anything into action," Los Angeles-based sex therapist Tammy Nelson advised. "Talking about the potential positives as well as the pitfalls of a possible exploration can prevent problems that could come up later. The more you talk about the issues before they happen the better."

A therapist's experience in working with couples pursuing ethical non-monogamy can help you weigh the potential pros and cons, guide you through the process and provide you with a neutral, safe space to discuss things.

Establish ground rules

Determine what ethical non-monogamy looks like to you both and agree on your parameters - more rigid rules may be best when starting out - and plan to keep the conversation going.

"I see dozens of couples a year who come to therapy to try and negotiate their expectations in advance," said Kimberly Resnick Anderson, a sex therapist in Los Angeles. "Couples who do their homework ahead of time have a much better success rate than couples who jump right in without preparation.

"Even couples who prep responsibly are often surprised by their reactions to certain situations and need to renegotiate boundaries."

In my professional experience, the couples who succeed at non-monogamy often don't require many rules at all, because they trust each other, prioritise the primary relationship and hold each other in mind throughout the process.

Redefine failure and success

If ethical non-monogamy doesn't work for you - or leads to a breakup - that doesn't mean it's a loss. "Consider a couple with children who, without ethical non-monogamy, would have split up, and for whom non-monogamy stabilises their relationship," New Jersey-based sex therapist Margie Nichols said.

"Eventually, that stability doesn't last, but ethical non-monogamy allows the couple to uncouple consciously and take time with the process," Nichols said. "Because of the thoughtfulness, the family can remain living together or near each other and still love and care for each other, and there is no bitterness or rancour between the two. I'd call that a success - despite divorce."

In the end, couples who succeed are fiercely committed to their primary relationship: They protect it, cherish it and care for it. They ensure that their foundation is solid and secure, and they continue to grow and expand as a couple in ways beyond sex. Non-monogamy may be an exciting new chapter for a couple, but it doesn't mean the story of their relationship comes to an end. It should feel like an exciting beginning.