'Thirty-eight-year-old men do not suddenly start buffing up the leaves of houseplants for no reason'

I let myself in, calling out his name, crossing my fingers that today might be the day he had decided to go in late. It was still only a quarter past nine but deep down I knew he’d already be at his desk. He wouldn’t be home till half six, quarter to seven at the earliest.  And I hadn’t even dared think about the fact that he might go out straight from the office. When I spoke to him last night – just before I boarded the plane, although he didn’t know that – he didn’t mention any plans, but these things change.

The moment I opened the door I knew something wasn’t right. The flat looked tidy, for a start. And there was a smell I didn’t recognize. Just a hint of it, mixed in with Jack’s earthy blend of coconut shower gel, takeaway curries and laundry with a hint of unwashed gym kit. I sniffed loudly, trying to work out what I was finding so unsettling. Could it be me, a faint trace left in my possessions, even though I hadn’t been back since Christmas, over three months ago?

I ditched my case and my computer bag and snuffled my way around the flat like a bloodhound. There was more evidence of extreme tidiness  –  the dishwasher was empty and everything put away, papers were stacked neatly on the coffee table; even the remotes were in a straight line. Maybe he’d invited his mum up, it occurred to me. I should have checked with her, let her in on my secret. He probably wants to show her how well he’s coping without me. I know how concerned she was when she heard work was taking me to New York. Maybe she was here already and she’d just gone out for the day, leaving a lingering, unidentifiable but most definitely female scent behind her.

I jumped as Oscar, our portly black cat, appeared out of nowhere and ran towards me. Grateful that he remembered me, I picked him up and made a fuss of him, but I was distracted. I looked in the fridge for his food.

Hummus? Jack thinks the only thing hummus is good for is grouting the bathroom. He thinks it tastes like old sofa cushions, although when he’s ever tasted those I have no idea. I shut the fridge door, plonked a handful of Dreamies down for Oscar, who looked at me, disappointed.

I checked in the spare bedroom for signs of life. The bed was stripped and piled up with junk, like it always is. Most of it has been there since the day I moved in four and a half years ago. Pictures we’d never got around to hanging, two tennis racquets we’d used once on holiday, a lamp neither of us liked. No visiting mother, then. I went back out and along the windowless hall. In the bathroom, I stopped short. There was a little cluster of girly toiletries on the windowsill. None of it belonged to me. Shampoo for fine hair. Toner for combination skin. I suddenly felt light-headed. Put out a hand to steady myself on the sink.

In the bedroom, the bed was made. I don’t think I’ve ever known Jack to make the bed in the five years we’ve been together. Not because he’s lazy, he just doesn’t see the point. He’s only going to get back in and mess it up again. There was an unfamiliar suitcase on my side. I flung it open, riffled through the clothes inside. She was a size eight, whoever she was. In the wardrobe, a row of dresses, blouses and skirts edged my own stuff to the far corner. Some of them looked familiar, but I couldn’t work out why. The labels revealed they were from Zara, Top Shop, Maje. Half my friends probably have the same things.

I resisted the urge to phone Jack to demand answers. He didn’t even know I was in the country. I retrieved my bags and made sure I’d left no trace behind. Then I exited the flat and headed down to the street. I went straight to the park across the road and sat on a bench. I needed time to think.