For eleven years, the last thing Daniel and I did each night was read in bed, our two tablets glowing in the dark like a pair of little hearths. We shared one account. It started as a frugal thing back when we were broke newlyweds in a one-bedroom over a laundromat, and it never stopped being ours. His thrillers, my historical novels, the parenting books we bought when Mara was born, the cookbook we never opened. One library, two readers. I used to think there was something tender about it, the way our reading lives pooled together in the same digital shelf.

That shelf is how I found out.

It was a Tuesday in October, unremarkable in every way. Daniel was downstairs on a "work call" that had been running long for weeks. I was propped against the headboard, reaching for my place in a novel about a lighthouse keeper, when the home screen finished syncing and a new cover slid into the top row. I had not bought it. The title sat there in plain gray letters, and I read it three times before it actually landed.

*How to Leave Your Wife.*

I remember the specific, stupid thought that arrived first: there must be a mistake, a recommendation, an ad. But it was in our library. It was downloaded. And when I tapped it open, the device did the thing it always did for us, the thing I had loved for eleven years. It showed me his highlights.

Daniel was a highlighter. He marked passages the way other people dog-eared pages, dragging his finger under the lines that struck him. In our shared books I used to find his notes like little love letters left in the margins. Now I watched his yellow underlines bloom across chapter after chapter, and they were a different kind of letter entirely.

He had highlighted a section on moving money quietly before filing. He had marked a paragraph about which accounts a spouse can open without the other's knowledge. He had underlined, twice, a line about "protecting a new partner from financial exposure during the transition." A new partner. The phrase sat there in his own deliberate stroke of yellow, and the whole room seemed to tilt very slowly to one side.

I want to tell you I confronted him that night, but I didn't. I sat there for almost an hour while the lighthouse novel went dark in my lap, scrolling through the architecture of my own undoing. He had not just been reading about leaving. He had been studying it. There were notes typed in his own words at the ends of passages, terse and practical. "Ask J about the lease timing." J. I did not know a J. I knew, suddenly, that I would.

The next days were the strangest of my life. I made his coffee. I packed Mara's lunch with the crusts cut off the way she liked. I watched my husband move through our kitchen, kissing the top of my head on his way out, and I knew the contents of his mind better than he did, because I had read his marginalia. He thought his planning was invisible. He had no idea the same cloud that carried his thrillers to his nightstand had carried his confession to mine.

I started paying attention to the small things I had been forgiving for a year. The phone that now lived face-down. The gym bag that smelled of a perfume that was not mine. The way he had grown gentle with me lately, almost guilty-gentle, opening doors, asking about my day, the tenderness of a man already half out the door and trying not to slam it. I had mistaken it for us getting better. It was him getting ready.

When I finally laid the tablet on the kitchen table between us, open to the page about hiding assets, he went very white and very still. He did not ask how I knew. He looked at the screen, at his own yellow lines, and I watched him understand that he had been keeping a journal of his betrayal in the one place we had always shared. He started to say my name. I held up my hand.

"You highlighted the part about protecting her," I said. My voice did not shake, which surprised us both. "You never once highlighted anything about protecting Mara. Or me."

He didn't have an answer for that. There isn't one.

We are divorcing now, and his lawyer is, ironically, very good. But I had a four-month head start, because a man who reads a manual on disappearing forgot that he was reading it out loud, to me, every single night. I kept screenshots of every page. The truth was already on my nightstand, glowing softly in the dark, waiting for me to look up from my own book and finally read his.