It started with a notification I almost swiped away without thinking.

It was a Tuesday, the dull middle of an ordinary week. I was on the couch with a mug of tea going cold on the armrest, half-watching some cooking show, scrolling through my phone the way you do when you are too tired to actually be entertained. Instagram showed me one of those "suggested for you" rows along the top, the little carousel of accounts it thinks you might know. I usually skipped past them. Strangers, mostly. Old acquaintances. A woman from a yoga class I quit two years ago.

But this one stopped my thumb.

The account had no real name, just a string of letters and a couple of numbers, the kind of handle people make when they want to lurk without being seen. No bio. Only a handful of posts, all reposted memes. And one profile picture: a dog, sitting on a patterned rug, head tilted, one ear flopped inside out. A scruffy little terrier mix with a white blaze down its nose.

I knew that dog.

I want to be clear about how strange this was. I am not a person who memorizes dogs. But I had seen this exact animal before, on a different phone, over my husband Daniel's shoulder, months ago, when I asked who he was texting and he turned the screen away a little too fast and said, "Just a guy from work, sending me his dog." I had laughed. He had laughed. I had completely forgotten about it until that white blaze was sitting in the palm of my hand, recommended to me by a machine that knew something I did not.

I told myself I was being ridiculous. Lots of dogs look alike. I told myself this firmly, the way you tell a child there is nothing under the bed, while you are already kneeling down to check.

I clicked the profile. Then I clicked the dog photo to make it bigger. Same rug. Same inside-out ear. There was a little ceramic bowl in the corner of the frame with a name painted on it in blue. I had to zoom until the picture went grainy, but I could read it. A name I had heard Daniel mention exactly once, in passing, the name of a coworker's dog, said so casually it had slid right past me at the time.

I sat very still. The cooking show kept going. Someone on the television was very excited about caramelizing onions.

Over the next hour I did the quiet, methodical work that a part of me had apparently been preparing to do for a long time. I scrolled the account's few followers and the even fewer accounts it followed. It followed almost nothing, which is what you would expect from an account built for one purpose. But there, tucked in the short list, was me. My account. Followed three weeks earlier.

That was the part that made my stomach drop, because it made no sense for a stranger to follow me, and perfect sense for someone watching me. I understood then what I was looking at. This was not a random suggestion. Somebody had made this little ghost of an account to keep an eye on my life, to see my posts, my stories, the photos I put up of our weekends and our garden and our perfectly normal marriage. And in the process of building their hiding place, they had slipped, linked it to something the algorithm could trace back, and the machine had cheerfully introduced us, the way it introduces anyone it thinks shares a connection.

We did share a connection. We shared Daniel.

I did not scream. I did not throw the phone. I went into the kitchen and washed the two cups in the sink and set them on the rack, and I noticed my hands were steady, which surprised me. When Daniel came home an hour later and kissed the top of my head and asked what was for dinner, I looked at him and saw, for the first time clearly, all the small turned-away moments of the last year laid end to end like stepping stones across a river I had not known I was crossing.

I waited until after we ate. Then I slid my phone across the table, the dog filling the screen, and I asked him to tell me whose it was.

He went the color of the cold tea I had left on the armrest.

I think about that suggested-follow row sometimes now, the casual cruelty of it, a thing built to track me handing me the truth instead. People are so careful with their lies. They sweep the texts, they clear the history, they turn the screen away. They never think the betrayal will arrive gift-wrapped by a phone that simply assumed two women watching the same man must surely already know each other.