I almost laughed. Not from humor but from the sheer altitude of the absurdity. “You weren’t worried,” I said. “You were tracking us. There’s a difference.”

This was not the first boundary she had pushed in the last year. It was not the fifth. Over the previous six months there had been the afternoon she appeared at Lily’s gymnastics class without telling anyone she was coming, claiming she had simply wanted to watch. There had been the phone calls to Lily’s school inquiring about pickup schedules, which the school had mentioned to me in passing because they thought I knew. There had been the afternoon I was home sick and Diane let herself in with an old spare key to leave soup on the counter, and I had found her in my kitchen, and she had seemed genuinely puzzled by my reaction. Each time it happened, each time I brought it to Mark, we would talk about it and land in the same place: it’s just how she is. She means well. Let it go.