My ex-husband, Jordan, arrived at our son’s pool party with Percy, the woman he had been seeing behind my back. I was standing beside Clark, the actor I’d hired to pretend to be my boyfriend, when Jordan looked us over and started laughing.

“He’d never be with you,” Jordan said. “Have you even looked at yourself in the mirror?”

A few people nearby heard him. My son was turning fifteen that day, and I had promised him a big party for his family and friends. I wanted the attention on him. Instead, for a few seconds, it was on me.

Clark didn’t answer Jordan’s insult. He smiled, held out a small gift box, and said he had a little something for the birthday boy’s father too.

Jordan opened it. A spring-loaded rubber snake jumped out. He screamed. The sound carried across the yard, and people turned to look.

That was the part I had not expected. Clark had brought a cheap prank toy, and Jordan had no idea what was inside. The surprise was harmless. What happened around it was not.

I had spent twenty years believing Jordan and I were happy. He proposed just after college, and we built a family together. We had four children. I never thought of our marriage as something that could be taken apart by a message on a phone.

Then, while I was holding our six-month-old daughter, another woman’s text appeared on Jordan’s screen.

I asked him to explain it. He didn’t try to make it sound better.

“I’m with Percy now,” he told me. “We’ve been together for over a year. I don’t want to waste any more time on a woman who’s no longer attractive to me.”

I remember the words clearly. I wish I didn’t. I asked him if he had been seeing her while I was pregnant. He said he had. Percy worked as his secretary, and she was about ten years younger than he was.

I was holding our baby while he told me he no longer wanted me. I kept asking questions, though I already knew enough to understand what he was saying. The divorce that followed was one of the hardest periods of my life.

By the time our son’s birthday came around, the separation was part of our family’s ordinary arrangements. The kids still had a father. Jordan and I still had to communicate. I tried to keep the birthday separate from everything that had happened between us.

My son wanted a big pool party with the whole family and his friends. I wanted to give him that. I also wanted to believe I could be in the same place as Jordan without feeling small.

Then his message came.

“I’ll bring Percy. She’s part of my family too.”

I read it more than once. It wasn’t the fact that he was bringing Percy that got to me. It was the way he announced it, as if I had no say in how that day would feel for our children or for me.

I typed a reply, erased it, and typed something shorter. I told him she could come. I did not want to make our son choose between his parents at his own party.

But I also wanted Jordan to see me with someone. I wanted him to believe I was doing fine without him. That is not a flattering thing to admit, but it was true.

I contacted a talent agency and explained what I was looking for: someone who could pretend to be my boyfriend at the party. They connected me with Clark. When we met, he was so tall and good-looking that I wondered why he had agreed to this at all.

I nearly called the whole thing off. I told him I wasn’t sure I could go through with it.

“Don’t you want him to see how happy you are without him?” Clark asked.

I said I did. I also knew I wasn’t exactly happy. I wanted Jordan to think I was, which wasn’t the same thing.

“You don’t have to prove anything,” Clark said.

“I know,” I told him. Then I decided to go ahead anyway.

The party was meant to be simple: our son, his friends, family, the pool, and a birthday celebration. I wasn’t trying to put on a performance for everyone there. I just wanted to get through Jordan’s arrival without being reduced to the woman he had rejected.

When Jordan came in with Percy, he greeted people as though nothing between us had changed. Percy stayed close to him. I stood next to Clark and tried not to look as if I were waiting for Jordan to notice us.

He noticed. He looked at Clark, then at me, and laughed.

“He’d never be with you,” he said. “Have you even looked at yourself in the mirror?”

I felt my face tighten. I wanted to answer him, but I couldn’t find words that didn’t sound like I was defending my right to be wanted.

Clark didn’t raise his voice. He didn’t tell Jordan who he was or explain the arrangement. He just offered him the box.

“I brought a small gift for you too,” he said.

Jordan looked at the box, then at Clark. “For me?”

“Just a little something.”

Jordan opened it. The rubber snake sprang up. He jerked back and screamed, and people around the pool turned toward him.

For an instant, nobody spoke. Then one of the guests laughed. Someone else covered their mouth. My son looked from his father to the box.

Jordan’s face changed as soon as he realized it was a toy. He looked at Clark.

“What was that for?”

Clark didn’t pretend the prank had been accidental. “You laughed at her before you knew anything about me,” he said. “I wanted you to see how it feels when everyone’s watching you.”

“You set me up.”

“I gave you a gift box,” Clark said. “You opened it.”

Jordan turned toward me. “This whole thing is staged.”

I could have denied it. I had brought Clark there to look like my boyfriend, and Jordan had guessed the main fact. I didn’t want to lie to him in front of our son.

“Yes,” I said. “I hired him to come with me.”

Jordan looked satisfied for half a second, as if that answered everything. “So you admit it. You brought a stranger here just to make me jealous.”

“I wanted you to think I was doing fine,” I said. “I was hurt when you told me I wasn’t attractive anymore. I wanted you to see me with someone who chose to stand beside me.”

Clark glanced at me but didn’t interrupt.

Jordan scoffed. “You could have just said that.”

“You could have just not said what you said to me,” I replied.

Percy had been standing beside him, quiet through the exchange. Jordan looked to her as if he expected her to take his side. She didn’t. She looked at the box, then at me.

“Can we not do this here?” she said.

“It’s already happening here,” I told her.

Jordan started to say something, stopped, then tried again. “I was joking.”

“No,” I said. “You wanted people to hear you.”

He looked toward the guests. “This is ridiculous.”

My son came over. He didn’t raise his voice. He looked uncomfortable, and I wished we had managed to keep the day from turning into this.

“Dad, can you stop?” he said. “It’s my birthday.”

Jordan’s expression changed again. The people around us weren’t laughing now. The box sat open near him, the toy lying where it had sprung out.

“I’m not trying to ruin your party,” Jordan said.

“Then don’t,” our son answered.

Jordan glanced at me, waiting for me to soften it or smooth things over. I had done that before. I had stepped between his words and the children, trying to make things easier for everyone. That day, I didn’t tell my son to ignore it.

I told Jordan the party was for our son, and if he couldn’t let the insult go, he should leave.

“You’re asking me to leave?” he said.

“I’m asking you not to keep doing this here.”

He looked at Percy. She didn’t tell him to stay. After a moment, he turned away from the group and started toward the exit. Percy followed him.

My son stayed with his friends. The party went on, though I could tell he wanted a little time before anyone brought up what had happened. I didn’t make him talk about it. I went back to being his mother at his birthday party, not the person Jordan had tried to make me feel like.

Clark stayed nearby, but I stopped treating him like proof of anything. I thanked him for stepping in, and he said he was sorry the prank had become a scene. I told him it had been Jordan’s scene first.

“I thought I could make him see I was fine,” I said.

Clark nodded. “And are you?”

I didn’t have a quick answer. I was still hurt. I was also the person who had let Jordan know what he said was unacceptable and then watched him leave when he wouldn’t stop.

“I’m getting there,” I said.

The rubber snake was a silly gift. Jordan’s insult was not. By the end of the party, I no longer needed him to believe I was happy.