It was a chilly summer morning at the cabin. My boyfriend was asleep in the bedroom as I made my way to the kitchen to fire up the wood stove and put on a cup of tea—not just to ward off the frost but to ward off a creeping sense of sadness, too.

Sean and I weren’t in a fight, exactly, but we weren’t exactly not in a fight either. I couldn’t figure out what was going on; I just knew that everything seemed to vibrate with an unspoken tension. An unsettling sense of disconnect.

The kettle started its piercing whistle and I pulled the pot off the burner quickly, so as not to wake Sean, pouring the boiling water into the chipped stoneware cup that held my Earl Grey tea bag. I made my way to the porch to reflect, facing east catch the rising sun, and read the bag’s fortune: “Sometimes people change and forget to tell each other.”

I burst into tears.

The words, a slight variation on a quote from the playwright Lillian Hellman, embodied everything I felt in that moment. Something had changed. Sean had changed, or maybe I had, or maybe both of us. Or perhaps it was neither of us that had changed but instead what existed between us—that indistinct, shapeless entity called love.

It was hard to put a point on it, but the carefree nature that had defined our early days together suddenly felt fraught with questions. I still loved him. I was pretty sure he still loved me. But there was a new texture. What had once felt deep and uncleavable now seemed slippery to the touch.

Within a few days we would call it quits; the split was as friendly as they come. We both felt the difference. We both agreed that our love, while still there, had rearranged itself without our consent.

Love is like that. So often, we think of it as a solid state of physical and mental connection that drives a relationship. But love, like the people who experience it, is also a force of nature, an organic energy that contracts and expands with every breath, constantly changing shape, sometimes to the smallest of degrees. It’s difficult to pin down, to constrain, to hold to any one set of expectations or beliefs.

The love between Sean and me had somehow extracted itself from our relationship. It still existed, out there in the ether, but we had drifted apart as restless twentysomethings often do, in search of our own deeper meanings and new adventures.

Over the years I’ve often thought back to Sean and the words on that tea bag—first with sadness, then nostalgia, and now with a sense of understanding as I navigate my marriage.

I’ve been with my husband more than 18 years. Over the years we’ve moved in together, exchanged vows, and changed addresses. We’ve experienced prosperity and financial turmoil. We’ve faced the deaths of friends and a parent. We’ve regretted past decisions and planned our future. We’ve fought and made up, fought and made up, fought and made up.

Fundamentally, I believe we are still the same two kids who fell in love over a shared passion for rock’n’roll, 1960s films, and all things vintage. At our core, we are those people.

At its core, our love, however, has changed so much.

Love changes us biologically—from the initial physical attraction and pangs of infatuation into a rewiring of the brain that imbues our partners with a sense of security and safety. Indeed, scientists have tracked the evolution of love, from the obsessive early stages of serotonin overdrive and dopamine-driven infatuation to the later, more enduring stages built on chemical attachment.

One can’t argue with chemistry, but inherently we realize all of this is intangible, too. The effects of love’s mutations are ethereal. All the science in the world won’t help you navigate the journey.

It’s taken my husband and I years to figure out how to weather the drifts and storms of change. Sometimes it sneaks up with a quiet and cunning that brings about a sense of disorientation. Other times we’ve been able to identify or even predict its arrival. One such moment came last year when the purchase of a new home and the death of my biological mother dovetailed into an emotional storm, setting in motion some of the deepest ripples across our marriage.

While buying our home felt like one of the most serious commitments we could make—at least on paper, more so than even marriage—news of my mother’s terminal illness fractured everything. Even as he consoled me, I think my husband knew how her impending death would not just remake my world, but also disturb the very air between us.

“This is going to change everything,” he told me right before I flew to Texas to be at her bedside. He meant it would change my perspective on life; but I knew that it would also alter our marriage. And to be certain, watching my mother—whom I really didn’t know very well—slip away with my stepfather at her side, cast the love I shared with my husband into a new chemical property, coating it with an amber resin of gratitude and resolve. Amber, of course, is a substance that can change from something solid into a suspended liquid state and back again.

Any relationships we hold dear—lovers, best friends, siblings, parents— change. There is growth and loss, there is birth and bloodletting. Love is ever-shifting. I’m learning to hold on lightly and let it drift, change paths, find its own way.

Rachel Leibrock is a writer and editor living in Northern California. Names have been changed.