At three in the morning, Sarah came home expecting the apartment to look exactly as it had when she left it.
She expected the lamp beside the couch to be on, dinner to be wrapped in foil, and me to be awake pretending I had not spent the night watching the clock.

She expected to find a man who would ask where she had been, swallow whatever answer she gave, and apologize for asking in the first place. What she found instead was an empty half of a home and a note on the kitchen counter.
You said we were basically over. I took you seriously.
She would tell me later that she stood there for nearly ten minutes, reading those words until they stopped looking like words. By then my brother and I were miles away, my belongings stacked against the wall of his spare room, my phone lighting up on a nightstand where I could barely bring myself to look at it. Three days later, Sarah stood crying outside the door of my new apartment and asked me how I could leave so easily. I remember the question because nothing about leaving had been easy, and nothing about staying had been easy for a very long time.
To explain that night, I have to go back four years, to a college library where I was twenty-two and sitting behind a computer that kept freezing. Sarah appeared beside my table carrying a coffee, a notebook, and a stack of books that looked ready to fall out of her arms. She asked if the chair across from me was taken, and when I shook my head, she dropped into it with a sigh that sounded like a performance for an audience of one. Within five minutes she had made me laugh hard enough that the librarian looked over her glasses at us.
Sarah had that effect on people. She could make an ordinary Tuesday seem like the beginning of something extraordinary, and when she looked directly at you, it was easy to believe you were the only person in the room. She talked fast, switched subjects without warning, and told stories with whole conversations acted out in different voices. I was quieter, the kind of person who thought through a sentence before saying it, and I mistook the difference between us for balance.
She asked what I was studying, and when I told her I was trying to finish a project that had already taken three weekends, she leaned across the table to look at the screen. "You always work this hard?" she asked. I told her I worked as hard as I needed to. She grinned and said, "That sounds exhausting. You need someone to teach you how to have fun."
For months afterward, she was the person who dragged me into the parts of life I normally watched from a safe distance. We went to concerts in cramped rooms with sticky floors, took drives without destinations, and stayed up until dawn talking about the places we wanted to see. She called me her calm place, and I called her my spark. At the time, neither of us understood how dangerous it can be when two people decide the other's personality is supposed to repair their own.