I need to tell you who Kat was to me, because none of the rest of this makes sense without it. Kat and I met in our first week of college, at Chapel Hill, in 2008. We were assigned to the same freshman hall. She was from Memphis. I was from a small town in Virginia. She was the kind of person who walked into a room like she owned it, and I was the kind of person who walked into rooms trying not to be noticed, and for some reason that only makes sense when you are nineteen, we became

inseparable. She held my hair when I threw up after the first party of my life. I held hers at her brother's funeral when we were twenty-two. She was maid of honor at my wedding in 2019. Our husbands had become, over the course of our late twenties, actual friends — not just dragged-along-by-the-wives friends, but real friends, who would text each other without us and who would plan golf weekends together. We were, in every visible way, the closest version of two couples you could be. I had told Kat things I had not told Owen. Kat had told me things she had not told Derek. We had, before my wedding, written each other letters we had planned to open on our fiftieth birthdays. I had been planning to open mine in eighteen years.