There is a photograph somewhere of the two of us sitting cross-legged on that carpet with takeout containers between us, and I looked at that photograph for a long time in the months after all of this, trying to find something in his face, some early edge of it.

It isn’t there.

I’ve looked.

He was twenty-six and happy.

Nina was born when I was twenty-four.

Sam came three and a half years later.

The change, when it came, did not come as an event.

It came as an arithmetic.