Romantic relationships used to be simpler. Traditionally, most couples were monogamous, while a smaller group explored open relationships—where each partner knowingly and consensually engaged with others outside the relationship.
That was the landscape.
These days, relationships come in many forms: polyamorous, swinging, polyfidelitous, monogamish—and that’s just the beginning. The growing vocabulary around relationship types reflects the need to define the nuances that make each connection unique.
Understanding the difference between these styles isn’t just about semantics. It helps people communicate boundaries, navigate desires, and honour consent.
This guide breaks down some of the most common types of non-monogamous relationships and how to tell what might work best for you and your partner(s).
Ethical non-monogamy
Ethical non-monogamy is a broad term that includes any relationship style where exclusivity isn’t expected—provided it’s done with honesty and consent. The emphasis on “ethical” highlights that this is not cheating or secrecy. In ethically non-monogamous relationships, everyone involved knows about the arrangement and agrees to the dynamic, whether that involves dating, sleeping with others, or forming deeper emotional connections.
Open relationship
An open relationship usually involves a primary couple who agree that each person can sleep with others outside the relationship. These external connections are typically sexual rather than romantic, though feelings can sometimes develop—which may complicate the dynamic.
Every open relationship is different. Some couples set specific boundaries, like avoiding repeat partners, not sleeping with mutual friends, or skipping overnights and shared beds. Others might follow a “don’t ask, don’t tell” policy when it comes to external encounters.
At the core of any open relationship is the understanding that the primary partnership remains the priority. Clear communication and agreed-upon boundaries help maintain trust and emotional connection.
Swinging
Swinging is a more defined version of open relationships, typically involving sexual activities with others as a shared experience. Unlike solo encounters in some open dynamics, swinging is something couples usually do together.
This might mean attending swingers’ parties or engaging in private swaps with another couple. It’s framed as a recreational, mutually agreed-upon activity that forms part of the couple’s joint sex life.
The defining factor? Both partners are involved and present, either in the same room or within the same social setting. It’s about shared exploration, not individual relationships.
Monogamish
The term “monogamish” was coined by relationship and sex columnist Dan Savage to describe relationships that are mostly monogamous but allow for occasional sexual encounters outside the relationship—with full transparency.
Partners in monogamish relationships rarely engage in sex outside the partnership. When they do, it’s typically circumstantial—such as when one partner is away for work. These encounters are usually kept emotionally detached and considered casual.
This relationship style often operates under a “don’t-ask-don’t-tell” understanding, even more so than open relationships, where partners tend to engage with others more frequently and may be more open about those experiences. The focus in monogamish dynamics remains on maintaining the emotional and relational core of the primary partnership.
Polyamorous
Polyamory combines the Greek word poly (many) with the Latin word amor (love). People in polyamorous relationships have romantic, intimate or sexual relationships with more than one person at a time, with the full knowledge and consent of all involved.
Some individuals may identify as polyamorous even if they are only in a relationship with one person. In these cases, they’re simply open to the idea of forming romantic bonds with multiple people, and so are their partners. They may also be casually dating, even if they are currently in only one serious relationship.
It’s important to note that polyamory is not the same as polygamy. Polygamy typically refers to a marriage structure where one man has multiple wives, or more rarely, one woman has multiple husbands (a structure called polyandry). These arrangements are often linked to patriarchal traditions and are legally and culturally distinct.
By contrast, polyamory is based on mutual consent, transparency and equality. That’s why many in the polyamorous community strongly object to the terms being used interchangeably—they represent very different values and relationship dynamics.
Hierarchical polyamory
This form of polyamory introduces a ranking system among partners. Typically, there is a primary partner—someone with whom an individual lives, shares resources, and makes major life decisions. Secondary partners often receive less time, energy, or involvement in long-term plans. In some arrangements, the primary partner may even have “veto power,” allowing them to influence or prohibit additional relationships.
While the structure of hierarchical polyamory provides clarity and defined expectations, it isn’t without criticism. Many in the broader polyamorous community challenge the notion of prioritising relationships, pointing out that it can lead to feelings of inequality and emotional distance. Still, others appreciate the stability the hierarchy provides, especially in navigating complex emotions like jealousy.
As sex educator Gigi Engle explains, having a primary partner offers a sense of normalcy and commitment, while secondary relationships allow for distinct emotional or romantic experiences. For some, this structure provides a balance between deep partnership and the freedom to explore meaningful connections with others, all within clearly defined and agreed-upon boundaries.
Polyfidelity
Polyfidelity is a form of ethical non-monogamy where all members in a romantic and sexual relationship agree to be exclusive within the group. Everyone is considered an equal partner, and romantic or sexual activity outside of the group is not permitted. Depending on the number of individuals involved, this relationship structure is often referred to as a “closed triad” or “closed quad”.
“A common misconception is that everyone in a triad is open to dating or sleeping with everyone else,” explains Engle. “That may be true in some arrangements, but certainly not all.”
Which Type of Ethical Non-Monogamy Might Suit You?
Each style of ethical non-monogamy has its own advantages and challenges, which is why clear communication between partners is essential. Those looking to enhance their sex life without seeking deeper emotional connections may find swinging or a monogamish relationship more suitable. For people who value emotional intimacy and want to build a supportive relationship network, polyamory or polyfidelity may offer a more fulfilling path.
“Because poly relationships exist outside traditional relationship norms, many people create their own terms and agreements,” Engle explains. “Unlike monogamy, which often assumes total emotional and sexual exclusivity, polyamory involves layers and grey areas that are actively negotiated by everyone involved.”
Relationship dynamics can evolve over time. An open relationship may grow into a polyamorous one, while couples who have practised polyamory might later choose to return to monogamy—or explore a new structure entirely. The most important factor is open communication and a willingness to adapt as each person and partnership grows.
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