Opposite me, squatting solemnly under the cold, cloudless blue sky, are the huge white domed towers of the Saint-Sulpice church. The bells inside them are ringing loudly again now, sending clouds of pigeons fluttering out of the trees below.

It was those same bells that exploded around me an hour ago, as I sat up to see that Daff had disappeared, and I was definitely not in Balham any more.

My stomach lurched sickeningly when I realised where I was – when I was – but maybe, somewhere in the back of my mind, I always knew this might be one of the moments I would revisit. Even though I won’t actually see Daff today – there’s currently about three thousand miles and the Atlantic Ocean between us – what’s about to happen changed everything.

I pick up my coffee cup and lean over the railing, looking down on the square below. From up here on the eighth floor of number 39 Rue Étienne Marcel, the whole of Paris sprawls out in front of me, its spires and chimneys and iron roofs looking postcard-perfect. Down in Place Saint-Sulpice, tourists wrapped in long coats and thick scarves are milling about cheerfully around the edge of the huge three-tiered fountain, or taking selfies in front of the giant Christmas tree behind it.

Four years have flown by in the blink of an eye, and now I’m here: 25 December 2014. A day I’ve spent the past six years trying to forget, sometimes because of burning regret, other times because I feel guilty at how much I enjoyed it.

Last night is still so clear in my head. I just wanted one more day there, in that reality. But no: from the happiest moment I can remember with Daphne in a long, long time, I’ve been dumped here, right into the thick of one of our worst, bleakest, most desperate periods. A period in which – technically – we weren’t even together.

I swallow the last grainy dregs of coffee, and look back down at the card. One sentence jumps straight out at me, making my skin prickle with guilt: I hate to think of you all alone on Christmas Day.

Whatever I was on this day originally, I definitely wasn’t alone.

I pick the card up and step back inside the tiny, freezing apartment. The bare parquet floorboards squeal irritably beneath my feet, and I can hear muffled yells from the married couple upstairs. I wonder what it is about the French language that makes even bickering sound eloquent.

I slump back down onto the iron-framed single bed and stare up at the ceiling. And all I can think is: what the hell am I doing here?

First time around, the answer to that question was pretty straightforward. That stupid argument after Jamila’s wedding.