Polysecure: Attachment Theory and Non-Monogamy
Polysecure, by therapist Jessica Fern, published in 2020, explains how attachment theory applies to non-monogamy. Its central idea is that opening a relationship can shake the deep sense of safety we feel with a partner, and that security in non-monogamy has to come from how partners treat each other, not from the promise of exclusivity. The book gives couples and individuals a language for those fears and practical ways to build secure bonds with more than one person.
Here is our plain summary of the key ideas and how they show up in real life.
A quick primer on attachment theory
Attachment theory began as a way to understand how babies bond with caregivers. Researchers noticed that children develop patterns based on how reliably their needs were met. Later work showed that adults carry similar patterns into romantic relationships.
The commonly used labels are:
- Secure. You can be close without panic and apart without dread. You trust that your partner will come back.
- Anxious. You crave closeness and worry about losing it. Distance feels like danger.
- Avoidant. Closeness can feel like pressure. You value independence and may pull away when things get intense.
- Disorganised. A mix: you want closeness and fear it at the same time.
These are patterns, not life sentences. Most people show different patterns with different people and at different times.
The key ideas, in our own words
Monogamy can hide insecurity
Fern points out that in a monogamous relationship, part of a person's sense of safety often comes from the structure itself: the promise that "you are only mine". Take that structure away, as opening up does, and any insecurity it was quietly covering can come rushing to the surface.
That is why perfectly happy couples sometimes feel shaken in the first weeks after opening up. It does not mean the relationship is weak. It means something that was resting on the structure now needs to rest on behaviour and trust. If this is where you are, our guide on how to deal with jealousy in an open relationship is a practical companion.
Attachment is wider than childhood
Fern does not blame everything on your parents. She describes attachment as shaped by many layers: your own history, your relationships, your family, your community and the wider culture you live in. A culture that treats non-monogamy as shameful can make people feel less safe, whatever their childhood was like.
You can be secure with more than one person
A big argument of the book is that secure attachment is not a single slot. People bond with several caregivers, friends and family members across life. Fern sees no reason adults cannot form secure bonds with more than one partner, as long as each bond gets real care.
HEARTS: how partners build security
Fern offers a memorable set of ideas, spelled HEARTS. In our words:
- Here. Be present. Put the phone down and actually be with your partner.
- Expressed delight. Show that you are glad they exist, in words and in your face.
- Attunement. Notice what they feel and respond to it.
- Rituals and routines. Shared habits that say "we are still us", like a Sunday breakfast or a goodnight call.
- Turning towards after conflict. Repair after a fight, rather than drifting apart.
- Secure attachment with self. Be a steady, kind presence for yourself too.
None of these require monogamy. All of them are things a partner can do while also seeing someone else.
What this looks like in real life
Here is an invented example. Anna and James, from Amsterdam, opened up after twelve years together. The first time James went for a drink with someone new, Anna was surprised by how panicked she felt. She is usually calm and confident.
Using the book, they recognised an anxious pattern showing up because the old structure had gone. Instead of adding rules, they added rituals:
- James sends one short message during a date: "Having a nice time, thinking of you, home by midnight."
- The next morning is their breakfast, always, no matter what.
- If either of them feels wobbly, they say "I need some HEARTS" and the other drops what they are doing for ten minutes.
What Anna said afterwards:
"I didn't need you to stop. I needed to know you'd come back to me and be glad to see me."
That sentence is very close to the heart of the book.
For a partner with a more avoidant pattern, the work looks different. They might need to practise staying in a hard conversation a few minutes longer, or offering reassurance before they are asked. Neither pattern is bad. Each just needs its own kind of care.
Where Polysecure fits among other books
Polysecure is more psychological than most books on non-monogamy. It is less about how to set up agreements and more about why certain moments hurt so much. That makes it a great second or third book.
Good pairings:
- More Than Two, which looks at fairness, rules and hierarchy in polyamory.
- The Ethical Slut, which deals with shame, permission and consent.
- Mating in Captivity, Esther Perel's look at the tension between security and desire, which makes an interesting contrast.
Some readers find parts of the book dense or clinical. If that is you, read the HEARTS section first and come back to the theory later. And if old wounds feel big, it is worth talking to a therapist who knows non-monogamy, in the US, Canada, the UK or wherever you live.
Who should read it
Read Polysecure if opening up has made you feel shakier than you expected, if you and your partner have different reactions to the same situation and keep misreading each other, or if you are polyamorous and want deeper tools for holding several bonds. It is also useful for anyone who suspects their jealousy is about something older than this relationship. Our guide on new relationship energy covers another moment where attachment fears often surface.
A closing thought
Security, in Fern's view, is something partners keep making for each other, one present evening and one repaired argument at a time. That fits how we like people to meet too: slowly, kindly, a coffee first. If that feels right, you are welcome to join Rope & Candy.
Questions people ask
What is Polysecure about?
Polysecure, by Jessica Fern, published in 2020, applies attachment theory to consensual non-monogamy. It explains why opening up can stir deep insecurity and how partners can build secure bonds with more than one person.
What does HEARTS mean in Polysecure?
HEARTS is Fern's short list of ways partners help each other feel secure: being here and present, expressing delight, attunement, rituals and routines, turning towards each other after conflict, and secure attachment with yourself.
Can you be securely attached to more than one person?
Fern argues that you can. People form attachment bonds with several people across life, and she sees no reason adults cannot feel secure with more than one partner when each bond is cared for.
Do I need to know my attachment style before opening up?
It helps but it is not a test you must pass. Knowing your patterns lets you spot what is happening when fear shows up, and lets you ask for what you need. A therapist can help if old wounds feel big.