It took years of living with B, my long-term partner, to realise the depth of her insomnia. Looking back, I can see how it was not visible or seriously troublesome for over a decade, though it was always there waiting to take full possession of her. Circumstances held it off, or at least masked it, until we moved into a small loft in Boston four years ago.

During our dating days, for example, there simply wasn't much sleeping going on. That was the least interesting way to spend our night-time hours. But this stage of our relationship was cut short by her admittance to a faraway art school. She moved to the other side of America and I was only able to visit her a few times. Her East Coast sleep routine was a mystery to me, while I clung firmly to my imaginary commitments in San Diego and perfected the power nap.

Upon reuniting, we soon learned we were pregnant. We had a baby very early in our relationship – before there was really a night-time norm. The disruption to our vague, ill-defined sleep patterns was total. Like all parents, we had to create new patterns, and we both understood that sleep was to be sacrificed. B's already-fragile sleep became even more tenuous as she became hyper-alert to any sound in the night that resembled a baby's whimper.

Really, in terms of design, she is simply not built for sleep. Her eyelids are thin, so light seeps in even when they are shut. Sound has no trouble finding its way into her head, particularly quiet repetitive noises, like a leaky tap or a ticking clock. The attractive lines of her small, sharp frame seem to resist repose – instead they suggest perpetual balletic movement – and she does not sink deeply into bed, even when exhausted. Meanwhile, my oversized head alone crushes pillows.

Of course, an even more significant difference is the way our minds are wired. Hers tends to churn on into the night, stirring up dizzying clouds of worry or thinking through the production challenges of her breathtakingly beautiful and complicated artistic endeavours, while mine is happy to go into screensaver mode after only minutes of idle. Or maybe even during conversation.

We had come to know this much about our differences when, while living in North Carolina, we began shopping for a house that would suit our needs – namely, a house that would allow us to have our own rooms. We eventually found the perfect place. Our daughter, who was now five, inhabited her own sky-blue cloud chamber sandwiched between our separate cells. B's room was outfitted with heavy curtains and her windows were cranked shut at night.

Down the hall, I received the phone and the cat at the end of the day. Any disruption by these potentially ill-mannered entities would be limited to my room, where I left the windows open to the roar of cicadas, the booming radios of passing cars and the drumming of a summer rainstorm. None of which prevented me from getting a solid seven hours of sleep a night, or more.

For about five years, this worked fairly well for us. I grew to enjoy having an entire bed to occupy, and the freedom to sleep without being self-conscious about snoring or, frankly, clocking obscene amounts of downtime over the weekends. A double-nap day wasn't uncommon, though at the dinner table I often chose to label these mid-day sleep sessions "research" just to give my inactivity an aura of purpose. I was, after all, writing a novel about dreams at the time.

Though this attempt of mine to justify my excessive sleep habit was positioned as a joke, there was some degree of guilt under it. I did, at times, feel like I was unintentionally flaunting my abilities before someone who longed for just a portion of the rest I was getting. I also wondered if there was something to the idea that I was hiding behind sleep, avoiding interaction – possibly even burying my head in the sand to avoid recognising that her sleep challenges were a serious health issue.

Often we would stay together part of the night. Then, at some point, one of us would rise and retreat to his or her own room. Of course, it was likely to be her, because I was usually deeply unconscious and going nowhere by midnight. In the mornings, our daughter and I could conduct our business while, schedule permitting, B would remain in her darkened chamber until noon, after lying awake most of the night.

Though our schedules were out of sync, the floor plan supported these lives of semi-isolation. The house was large enough to accommodate oddly overlapping sleep-defined rhythms of the day. We developed some livable patterns. We made it work. But all this changed when, a few years ago, we relocated into a small loft in an old warehouse building in Boston.

There were only three rooms – one for our daughter, a large central room with a bed that folded out of the wall, and a tiny room that we used as a library for B's many books. In this setting, her struggles became more visible to all of us. The close quarters made it more challenging to stay out of each other's sleep cycles. As the situation worsened, B took to trying multiple sleep locations each night.

Often her odyssey would begin with me, where I slept on the Murphy bed. The light would click off and the room would go dark. It's likely that I would have already been asleep or very nearly so, when she would push up against my side and wait for sleep to radiate off me in soothing vibes. But this rarely worked, my snores making things worse.

Soon I would feel her shift, then turn, then shift again. A couple more attempts to find just the right configuration – a secret, sleep-inducing pose of the body that eluded her – and, failing yet again, she would soundlessly rise out of the bed.

I watched her go in silence, though earlier in our relationship I would call after her as she slipped off into the night: "You OK?"

She would respond by telling me not to worry. "Sleep," she would whisper, giving both a gentle command and the name of the ghost she was chasing.

Carrying her pillow flopped over her shoulder, she would disappear into the small library where the walls were lined with her Russian books. If she couldn't sleep, at least she could read. There was a narrow bed in there, and sometimes she succeeded in dozing off, despite the disruptive sounds.

The room was not ideal for sleep because it shared a wall with the building hallway. The heavy steps of passersby could actually cause the room to vibrate and the old floorboards of the corridor creaked loudly with every step. The ding of the elevator could be heard throughout the night. If I happened to wake up I would sit up and peer over the couch, checking for light under the door – the sign of her ongoing wakefulness.

This would sadden me and make me determined to find some kind of miracle solution for her – maybe hypnotism or some kind of white noise machine. The night must seem endless, time passing so slowly. She was trapped in it, conscious of every passing second, and I could do nothing to help her escape.

Sometimes, later, she would return to the bed, easing herself back under the blankets. In my half-sleep I would note this. But in the morning, I would wonder if I had dreamed it, since her half of the bed would again be empty. I would rise and carefully pick my steps across the floor, in an attempt to avoid the creakier floorboards.

Often I would find her sleeping on the couch, with a pillow over her face, or a T-shirt or her hair over her eyes. Other times, I would believe she was on the couch, having seen or heard her there at some point in the night, only to find her missing in the morning. I would be strongly compelled to check if she was sleeping among her books, but also equally reluctant to risk waking her by opening the door. When I did check in on her, I would more often than not find her wide awake, reading in bed or sitting at her computer desk. "Did you get any sleep at all?" I would ask.

The response was usually a slow shake of the head.

When things got worse, B tried prescription drugs but side-effects of nausea and light-headedness undermined what little sleep they provided. She could somewhat rely on over-the-counter tablets for at least four hours of unconsciousness, maybe six on a good night. Nothing else – herbal or chemical – worked. Maybe a new approach would have some impact at first but, to our dismay, would eventually fade in effectiveness.

Despite all this, she still managed to complete lengthy animated films, teach a full load of courses and be adored by her students, serve on committees and juries, earn tenure at a prestigious institution and care for our daughter with Old World parental intensity. I could only watch in awe as she accomplished these things while living out of step with the rest of us, finding little opportunity for restoration within the relentlessly diurnal beat of civilisation, yet soldiering on.

To this day, sleep still eludes her, but we have all made changes that make it more possible for her to clock some decent hours. We both recognised that we needed more room, so I relocated to a nearby loft of my own, replicating our multi-room house arrangement. Our daughter has gone off to college and the cat has lost her youthful interest in stirring up nightly trouble, so nights are quieter and simpler these days.

Sometimes, dozing off in my own apartment a building away, I hear the murmuring of neighbours through the walls and I flash back to those nights in North Carolina. I believe, in my pre-sleep state, that we have travelled back in time. B has climbed into bed with our daughter in the room next door, as she did every night. I can hear her reading a bedtime story in Russian, followed by the usual giggles and songs.

Eventually they go silent and I dream that I play out my role. I emerge from my room to find them asleep in each other's arms. I collect the cat and the phone, shut off the lamp, and silently close the door behind me, hoping to find them both there, asleep together, in the morning.

• Kenneth Calhoun is the author of Black Moon (Hogarth)