I took the children away for the autumn half term, and when we came back he was gone.

My daughter, then 15, and son, 12, knew their father wouldn’t be there, and why: we had discussed it, rehearsing how it might feel. But I felt it in my bones, the shock of unlocking the door and stepping into the silent house knowing he wasn’t at home and never would be again.

A week earlier, a friend who’d been through her own divorce made a suggestion: ‘It’s brutal for the children if the furniture suddenly disappears. It’s their home and you don’t want them to feel it’s been ransacked. Maybe he could take his things gradually, over time, rather than in a great trolley-dash.’

This made sense to me, and thankfully it also made sense to the man who was to become my ex-husband.

So when the children and I came home, the paintings were still there, the lamps, the cushions. The blue and white vase – a wedding gift from some friends of his parents – stood on the mantelpiece, as it had done throughout the 17 years of our marriage.

There were a few gaps on the shelves where his books used to be and when I went into the kitchen I noticed he’d taken the fiddly gadget for making coffee. Whatever. I preferred the Melitta coffee filter cone anyway.

I carried my bag up to the room that had been ours but was now mine. Everything was exactly as I’d left it: my jersey over the back of a chair, a postcard tucked into the mirror frame, the bottle of Annick Goutal’s Gardenia Passion on the dresser. I’d discovered that scent during our engagement and wore it on our wedding day. I couldn’t imagine using it ever again.

His bedside table was bare – he’d taken the lamp – and the drawers had been emptied of chargers and nail clippers and blister packs of paracetamol.

Sitting on what was no longer his side of the bed, I remembered the click as he removed his spectacles last thing at night, the slight tug of the duvet as he reached over to switch off the light.

His cupboard scared me the most. I stood in front of it, preparing and then I made myself open the doors. A dozen wire hangers chiming on the rail – nothing else. Everything had gone: the suits, the jackets, the work shirts, the weekend shirts, the rack of ties (and, for good measure, all the wooden coat-hangers too).

I cried then, because he wanted a different kind of life, and it had ended so suddenly, and I could not protect the children from what was happening. And also because from now on I would have to do all of it on my own and I really wasn’t sure if I could manage that. For a moment I let it consume me: not just the sadness and loss but also the terror.

Nine years earlier I’d started to lose my sight to a rare autoimmune disorder affecting the optic nerve. By this point my sight was stable but I was registered blind, medication holding the thing at bay. I had a small amount of faded central vision left in one eye – it’s a bit like looking at the world through a loo-roll tube – but not enough to drive, read newsprint or see the stars.

I’d parked my career in journalism while waiting for a diagnosis and then, miraculously, found my way into fiction.

My first two books – Alys, Always and Her – had been best sellers. But my third novel, completed that spring, had not worked and I couldn’t fix it. I was facing the possibility that my writing career was over.

And now, aged 47, I also found myself unexpectedly alone.

I was doing my best to cry silently, but my daughter must have heard something because she came up the stairs and put her arms around me, and that made me cry even harder. We stood like this for a while.

Eventually we blew our noses and blotted our faces and went downstairs to watch Strictly.

At first, every morning was the same. When I woke up, the shock would hit me like an HGV. Will we have to sell the house? What will happen at Christmas? Who gets the dining chairs? I knew I needed to keep myself busy, but it’s hard to write fiction when your life has been upended.

I put the laptop away and laced up my walking boots.

I walked for miles most days, through crisp autumn sunshine and squalls of rain that blew the leaves off the trees.

My friends shuffled schedules to ensure I had company. An awful lot of weeping happened on these walks through London’s parks, but also a fair bit of stopping and clutching each other and screaming with laughter.

My friends kept me afloat that autumn, offering me everything from late-night phone support to solicitor recommendations and a steady stream of Beyonce/‘you got this!’ GIFs. The GIFs were satirical, of course, but they cheered me up anyway.

I made sure I was always home when the children came back from school, just in case they were in the mood to talk.

Every so often, I’d have a panicky thought about some piece of Separation Admin that needed my urgent attention, and then I’d push the thought away, like Scarlett O’Hara (‘I can’t think about that right now. If I do, I’ll go crazy. I’ll think about that tomorrow’).

To dodge the guilt, I threw myself into displacement activities. Not all of them were a waste of time.

In the months leading up to my husband’s departure, our home had started to manifest signs of neglect. I wasn’t sure if the children and I would still be living here in a year’s time, but the tattiness was bad for morale so I set to work.

Looking back at my Amazon history for that autumn, I see I’m ordering pliers, window locks, a sink plunger, superglue, tiny bulbs for the cooker hood.

During the marriage we both assumed I was hopeless at DIY, because of my temperament as much as my blindness, but here I was, high on YouTube tutorials, fixing a shower with brewers’ droop, and using a magnifying glass and matchsticks to pack out the stripped hinge on a kitchen cabinet.

Most surprisingly, I was enjoying myself.

I ran out of excuses once I’d bled the last radiator: it was time to tackle the admin.

Getting to grips with this new financial reality was a sobering process, but there was a certain grim satisfaction in assuming control, making my own decisions. I’d always believed I was financially incompetent, but maybe I’d underestimated myself on that front too.

By this point my ex had claimed the household items he wanted, but there was still plenty of his stuff left behind in bathroom cabinets, on top of wardrobes and under the stairs.

Disposing of this – tubes of verruca ointment, squash rackets, broken printers, jackets he’d never liked – turned out to be an exercise in catharsis, as warming and feelgood as feeding a bonfire. My power surged back with each trip to the charity shop.

Every item sold on eBay felt like an exorcism. Little things gave me big thrills. My ex’s status updates were getting on my nerves, but that, I realised, was easily remedied: mute, block, unfollow. I’d been liberated from the obligation to love him, and now there was no need to take much of an interest. Honestly, it felt tremendous.

It was dawning on me that I didn’t have to fall apart simply because that was how discarded women behaved in the pop songs, novels and films I consumed at an impressionable age.

Most marriages come unstuck for a small number of fairly banal reasons, and ours was no exception: the split was sad, but as time passed I found I couldn’t think of it as tragic.

One night, three or four months after my husband’s departure, I was putting out the recycling (no biggie. What was all the fuss about?), when I suddenly realised that those friends who kept sending me the ‘you got this!’ GIFs were right. I was going to be OK.

I had no time for those well-meaning people who, hearing of our separation, clasped their hands and gazed at me with sorrowful compassion, as if they were attending a funeral. I didn’t want anyone’s pity (which occasionally looked a lot like self-congratulation). As far as I was concerned, I was knocking it out of the park.

Sorting the house insurance or re-pressurising the boiler were only baby steps, but to me they felt like giant leaps, worthy of marching bands and glitter cannons.

So I was putting my house in order but I still didn’t know what to do with the wedding scent.

For several months the sight of the fluted bottle with its golden cap made my blood run cold. I’d adored that scent – the sucker-punch of sun-drenched waxy white petals both old-fashioned and a little bit hallucinatory – but now it had become an unwelcome reminder of everything I’d lost. Perhaps there was a way to turn that around. One morning, as if embarking on a laboratory experiment or a sacred rite, I sprayed a little on my wrist, and as the familiar fragrance enveloped me I told myself: this is mine, I want this back.

I performed this little ceremony every day for a fortnight, and by the end of the fortnight I had somehow managed to reclaim the scent. Instead of summoning up sadness and a sense of loss, it now reminded me of my determination, my resourcefulness, my refusal to cave.

I still loved it, but for new reasons. It meant more.

In my fiction I’m drawn to writing about women who, finding themselves at a crossroads, are forced to re-negotiate their identities, so it’s no surprise that, as I settled into my new life, I started to work on a novel about someone coming to terms with the sudden end of her marriage.

My protagonist Ruth’s circumstances and responses are quite different to my own, but we do have a few things in common.

Like her, I’m curious about the gap between what we say and what we mean. Like her, I wonder about friendship and the perils of trust. Like her, I’m fascinated, not always in a wholesome way, by the Best Lives taking place in the Instagram grids of friends, acquaintances and Gwyneth Paltrow.

So I kept writing the book and one day, as I was approaching the end, I reached a moment where the narrative needed the wedding-scent story.

It felt like tidy housekeeping, making use of it in this way. And as I saved the document and closed the laptop, I caught the faint scent of gardenia on my wrist.

• Other People’s Fun by Harriet Lane (£20, Weidenfeld and Nicolson) is out October 30.