The Complexity Theory of Love

There’s a moment I think about often from early in my work with one couple. The husband had been trying for weeks to explain what he wanted from his marriage. He wasn’t unhappy exactly. Or he was, but he couldn’t locate why. Every time I asked him to say more, he’d lean forward, and his whole body would tighten, and he’d say: I just want more. With a kind of intensity that made it clear the word wasn’t adequate. He knew it wasn’t adequate. It frustrated him that it was all he had. He just kept saying it over and over. I want more. I want MORE.

We kept working. Slowly, the relationship became safer. He became more able to sit with his wife’s gaze without bracing. She became more able to reach without fearing she’d be left reaching. The bond, as we say in my field, was securing.

And then one session, I asked him again. What is it you want? He was quiet for a long time. I watched him actually listen to the feeling rather than frantically search for words to cover it. And then he said, almost to himself:

I want us to feel like a kaleidoscope.

His wife and I both stared at him. It felt like something big was happening, like no one knew what a kaleidoscope was, but we all also knew exactly what it was.

Not because it was poetic, though it was, but because it was precise. He wasn’t describing more of the same thing. A single beam of light doesn’t become a kaleidoscope by getting brighter. It becomes one by having more facets to move through. He was describing something that had become more complex. More dimensional.

Passion is the felt sense of intimacy increasing.

I’ve been thinking about this definition for a long time, and I keep coming back to it because of what it implies: that passion is not a static thing you have or don’t have. It’s a felt response to movement. To change. To the sense that something between you is growing.

But here’s what I think we get wrong about that growth. We tend to imagine it linearly. More intimacy means more of the same intimacy, accumulated over time. And eventually, the thinking goes, you run out of newness. You know each other too well. The growth stops and so does the passion. This is the story Esther Perel tells so compellingly: that familiarity and desire are in fundamental tension, that we want what we can’t quite have.

I think that story is half right and half backwards.

Consider how a brain grows.

Not by adding neurons — you’re born with most of the ones you’ll ever have. A brain grows by forming connections between neurons. Synapses. Pathways. Patterns of activation that didn’t exist before. And from that increasing complexity, something emerges that couldn’t have existed in any single cell: a mind. Consciousness. The capacity for memory, imagination, love.

This is what scientists and mathematicians mean by emergence: the appearance of properties in a system that cannot be found in or predicted from its individual components. The mind is not in any one neuron. It arises from the pattern of relationships between them. It is, in the most literal sense, more than the sum of its parts.

A bond works the same way.

Early in a relationship, the increase in intimacy is fast and obvious. Everything is new. Every conversation reveals something. Every touch is information. The passion is intense because the intimacy is increasing rapidly. You can feel it happening in real time. This is that initial flicker. A single bright beam of light.

Then something changes. The easy newness diminishes. You’ve covered the surface. And here is exactly where most couples — and most cultural narratives — make the mistake. They interpret the slowing of that first rapid increase as the beginning of the end. The passion is fading, they think. We’ve lost something.

What they’ve actually entered is complexity.

Depth comes in. History accumulates. You’ve fought and repaired. You’ve disappointed each other and stayed anyway. You’ve seen each other sick, scared, boring, luminous. You know things about this person that they’ve never said out loud to anyone else, and they know the same about you. You have a private language. Shared griefs. Jokes that require no setup.

None of this is a diminishment of the bond. It is the bond becoming more dimensional and faceted. More like a kaleidoscope than a single beam of light.

Desire doesn’t disappear in a complex bond. It differentiates. It becomes more specific, more nuanced, more capable of surprise. Not because your partner is still a mystery, but because you both keep becoming. Two people in a genuinely alive relationship don’t stop changing. They keep discovering new parts of themselves and bringing those parts back to a bond responsive enough to receive them. That return, that ongoing revelation, is where desire lives.

The husband who said I want us to feel like a kaleidoscope couldn’t have said that in our first session. Not because he lacked the language (okay, that too), but because he lacked the felt experience. The bond had to secure first. He had to feel safe enough to listen inward, to let the feeling differentiate from a formless hunger into something he could almost see. What emerged when he did was not a simpler wish. It was a more complex one.

Couples who sustain desire over time are rarely the ones who’ve kept things exciting through novelty and distance, though that can work for a while. They’re the ones whose bond has become genuinely complex. Who have enough safety to keep changing as individuals, and enough aliveness between them to keep finding each other interesting.

They’re not in the initial, exciting flicker of brilliance anymore. They’re in something harder to name and harder to manufacture. Something that took years to build and that has a kind of luminosity that’s different in quality from the early brightness. Less blinding, more immersive, complicated, infinitely interesting.

A kaleidoscope.