Relationship and sex therapist Michelle Kasey explains the different types of non-monogamous relationships, why they’re on the rise, and the pros and cons of exploring them.

The purpose and expectations of modern relationships
have significantly evolved over time. Historically, people predominantly came together in marriage and partnership for financial stability, survival and to maintain social order. Today, as explored by renowned therapist and author Esther Perel, people seek partners who not only offer love and stability but also contribute to their self-actualisation, fulfilment and happiness.

In my six years of working with couples, I’ve observed a widespread desire to maintain passion in long-term relationships. Couples strive for deeper emotional connections, personal growth and erotic fulfilment – qualities that were often absent in the long-standing relationships of previous generations. The traditional model of monogamy is being reconsidered in a society where women are no longer solely financially dependent on men, the sexual revolution has expanded our exploration of sexual desires, and an increasing focus on personal development and therapy has made people more attuned to their authentic needs and desires.

Studies suggest that around 4-5 per cent of the US population engage in ethically non-monogamous relationships, with Millennials and Gen Z leading the redefinition of societal norms around sexuality and relationships. Though specific data for New Zealand is lacking, we might speculate that the figures are similar.

Understanding different styles of ethical non- monogamy (ENM)

Polyamory

This style involves multiple romantic or sexual relationships with the consent and knowledge of all parties. It emphasises deep emotional and romantic connections, not just sexual ones, and can range from hierarchical arrangements (with primary and secondary partners) to non-hierarchical structures where all relationships are considered equal.

Open relationships

Typically characterised by a primary committed partnership, where one or both partners are free to pursue sexual encounters outside of the relationship. Unlike polyamory, these usually focus more on sexual freedom rather than developing additional romantic connections.

Swinging

Often a social or recreational activity, swinging involves partners in a committed relationship engaging in sexual experiences with others, such as swapping partners with another couple, attending sex parties, or having threesomes. It prioritises sexual novelty over emotional connections.

Monogamish

Coined by columnist and podcaster Dan Savage, this term describes relationships that are predominantly monogamous but may include occasional sexual encounters with others. This style allows for limited sexual exploration while maintaining a strong emotional bond between primary partners.

Relationship anarchy

This approach rejects conventional relationship hierarchies and labels, prioritising personal freedom and equality in connections. Relationship anarchists seek to allow relationships to organically find their own depth of intimacy, degree of commitment, and unique dynamic independently of societal norms.

The “ethical” component of ENM is critical – it’s practised with full consent, honesty and respect for everyone involved. This distinguishes it from unethical practices like infidelity or coercing a reluctant partner into an open relationship.

Benefits and challenges of ENM

A core idea of ENM is that no single person can meet all of your needs. ENM can satisfy more of one’s emotional, intellectual and sexual needs, potentially alleviating pressure on a single partner. Having multiple partners can also broaden your network of support, providing you with a variety of perspectives and support styles. ENM can also be a profound path for personal growth. In practice, allowing more freedom for yourself and a partner usually requires you to overcome insecurities and strengthen your relationship with yourself.

Despite the shifting cultural stigma – where once it was more socially palatable to cheat than to be consensually non-monogamous – challenges persist. ENM is often misunderstood and stigmatised, leading many to act with discretion. Logistically, managing time and energy across multiple partners can be daunting and may strain relationships if not approached with care. The emotional labour of maintaining several deep bonds simultaneously can be intensive. ENM people need to be fantastic communicators in order to understand and navigate the complex needs and wants of more than two.

When working with couples who are considering opening up, I focus on helping them to build a secure foundation in their relationship, moving very slowly, and equipping them with the skills needed to manage the emotional complexity that typically arises during this transition.

For those curious about ENM, getting educated is essential. Books like More Than Two by Tristan Tarramino, Polysecure by Jessica Fern and The Ethical Slut by Dossie Easton and Janet W. Hardy are valuable resources. Consulting a therapist experienced in non-traditional relationships can also be beneficial.

Monogamy remains a valid and satisfying choice for many. No one relationship style is superior; what matters most is having the self-awareness and communication skills to determine what is true and functional for each person.

Michelle Kasey is an Auckland-based sex and relationships therapist who has worked with clients in NZ and around the world for more than six years. She is also a professional burlesque artist, champion pole dancer and writer. Visit michellekasey.com.