My husband texted: “Happy anniversary, babe. I’m stuck at work.” I was already there—watching him kiss someone else. Then a stranger whispered: “Stay calm. The real show is about to start.”

A man stepped beside me before I could take two steps.

“Don’t,” he said quietly.

I turned, furious. “Excuse me?”

He kept his voice low. “Stay calm. The real show’s about to start.”

He looked about forty, tall, sharply dressed, with the kind of face that had been tense for too long. He nodded toward the woman at my husband’s table.

“My name is Daniel Mercer,” he said. “The woman with your husband is my wife.”