I saved my sister by donating a kidney; then I discovered that I was having an affair with my husband, so I invited them to a dinner they would never forget.

When my younger sister, Clara, needed a kidney transplant, I donated mine to her.

I didn’t hesitate for a second. I didn’t do calculations. I didn’t ask for time.

When we were told it was compatible, I said yes before they finished the sentence.

Clara looked at me from her hospital bed and asked me, “Would you really do that?”

I remember looking at him and thinking: I chose the right man.

“Of course I do,” I said.

He started crying. “I don’t know what to say.”

“You can say thank you and then stop doing the drama for five minutes.”

He laughed and cried at the same time. “Thank you.”

My husband, Evan, squeezed my shoulder and said, “You’re saving his life.”

I remember looking at him and thinking: I chose the right man.

The surgery went well.

That thought turns my stomach now.

Clara and I were never the closest sisters in the world. We wanted each other, but some distance away. She was impulsive. I was wise. She liked to be the center of attention. I liked order. When we were little, we were fighting a lot. Still, she was my sister. When things went wrong, that’s what mattered.

Evan and I had been married for nine years. We had a daughter. We had a mortgage, we shared agendas, shopping lists and all those little customs of a marriage. It wasn’t exciting every second, but it was real. Or so I thought.

I discovered it by chance.