But how many people are actually polyamorous? Its tough to gauge the numbers, but its currently estimated that 4 to 5 percent of people living in the United States are polyamorousor participating in other forms of open relationshipsand 20 percent of people have at least attempted some kind of open relationship at some point in their lives. Those numbers, however, are likely to increase, as a 2016 YouGov study , found that only half of millennials (defined as under 30-years-old) want a completely monogamous relationship.

So what exactly is polyamory? How does it differ from open relationships? And why are we seeing a rise in interest and practice? Let's break it down.

Polyamory simply means youre open to the idea of both loving and having a serious romantic relationship with more than one person at a time. Poly comes from the Greek word meaning many, and amory from the Latin for love. Notice that its simply open to the idea of loving more than one person at the same time, meaning you can have just one partner, and still be polyamorous.

If this is the case, you and your partner havent found another person you want to call your boyfriend or girlfriend. Nevertheless, youre not opposed to falling in love with another person. Youd also be supportive if your partner found another serious partner.

Lia Holmgren , a NYC-based intimacy and relationship coach, shed some light on the major difference between open and polyamorous relationships. She told Mens Health, In polyamorous relationships, you build relationships with other people outside your main relationship, and the purpose isnt only sex but also emotional connection and support. She continued, In open relationship, you have one primary partner you have a sexual and emotional relationship with, but you are allowed to have sexual relationships with other people outside of the relationships that do not form into romantic relationships.

No two types of open relationships look the same. They each come with their own set of rules agreed upon by the couple. Some couples will agree that they only play together. Perhaps penetrative sex is off the table but other sexual activity is fair game. There are also couples who agree that they cant have sex with the same person more than once or let casual partners spend the night. Whatever you decide is completely fine, as long as both you and your partner follow the agreed upon terms.

Ethical non-monogamy is the umbrella term for all relationship styles that arent strictly monogamous, including polyamory, open relationships, and all the terms to follow. The word ethical is thrown in there to indicate that all partners are aware of the relationship dynamic. This differentiates ENM from people who are simply liars or cheaters.

Coined by relationship guru nearly a decade ago, monogamish describes relationships that are, for the most part, monogamous, but allow for little acts of sexual indiscretion (with the partners knowledge). These acts of indiscretion dont happen regularly; they typically take place when one person is out of town for work. The sexual flings are meaningless, and in my own personal experience talking to couples in monogamish relationships, they usually have a dont-ask-dont-tell policymeaning that they dont want to hear about whatever their partner did while out of town. This differs from most open relationships, where couples tend to share their sexual experiences to their partners (within reason).

In polyfidelitous relationships, all members are considered equal partners and agree to limit sexual and romantic activities to only those in the group. People will also call this a closed triad or closed quad depending on if there are three of four people in the relationship. The easiest way to think of polyfidelity is that its like monogamy, only with an additional member (or two).

Relationship anarchy, often abbreviated as RA, means that you can do whatever you want in your relationship, and its nobody elses business, explains Holmgren. You and your partner(s) make up your own rules without care for what is traditionally considered right or wrong.

Relationship anarchists are the we dont do labels of the relationship community. (Yet, ironically, they need a label to make that distinction.) They actively eschew any social norms when it comes to relationships, and dont want to categorize their relationship as being open, monogamish, or anything else (even if it technically fits into those categories).

Daniel Saynt, founder and chief conspirator of the members-only sex and cannabis club, New Society for Wellness (NSFW), attributes the increase in polyamory to numerous societal and cultural factors, but he focused specifically of four.

1. Many millennials grew up in broken homes or with parents in a loveless marriage.

Former examples of love from our childhood have had an impact, he explains. We realize the mistakes our parents made and strive not to repeat them. We don't want to get divorced because we still have scars from our past.

Since monogamy didn't work for many members of the previous generation, millennials are searching for other types of relationship formats.

2. Millennials are leaving organized religion.

"In line with marriage is the idea of 'sanctity' or something that should be holy in our eyes. Millennials are leaving the church in droves ," Saynt says. "We're seeing the hypocrisy of religious leaders. Many are rebelling against the principles we've been raised to believe were important to reach salvation."

Since the current generation recognizes how often traditional marriages fail and dont trust the churchs concept of marriage, We've formed our own thinking on what love, commitment, and sex means to us, which opens the door for loving more than one person.

3. There's an increase use of dating apps.

"Hookup culture is the norm and people now feel they have options when a relationship doesn't work out," Saynt says. "So, too, has the pool of potential partners increased. Both men and women are starting to wake up to the idea that having a single partner for life might not be as interesting as finding many people to play with.

This doesn't mean we don't want commitment, he clarifies. There's plenty of commitment in polyamorous relationships. We just don't believe that one person should be responsible for all our emotional and sexual pleasures.

4. There's been an increase in polyamorous representation in the media.

"Over the past 20 years, we've seen an increase in stories about polyamorous people, both real and fictional. Polyamory, Big Love, Unicorn Land, Me You Her, Professor Marston and the Wonder Women, and Monogamish have all provided people with a peek into the lifestyle. Saynt believes increased visibility has let people know that polyamory is a valid relationship style.

Whatever the factors are, theres no question societys interest in polyamory isnt a passing phase. Its here to stay, and you can expect to see even more articles discussing the various ways folks are embracing sexual and romantic relationships with multiple partners.

At least now, youll know exactly what they're talking about.