My Sister Planned a Lie Detector Contest for My Fiancé and Me at My Wedding—the Wedding Was Canceled After Taking It

I always thought my wedding day would be unforgettable for all the right reasons. Instead, it became unforgettable for a reason I could never have imagined. It all began when my sister brought a lie detector test to the wedding.

I’m Harlene, a 28-year-old teacher, and until recently, I thought I had the perfect life. My fiancé, Mark, and I had been together for five wonderful years, planning a future filled with love and laughter. That future vanished the moment my sister, Melissa, turned my wedding into a nightmare.

Let me explain.

A woman standing outdoors | Source: Midjourney

Mark and I met through a mutual friend five years ago, and from the moment we connected, it felt like we’d known each other forever.

He was very kind and sensitive to everyone’s feelings around him. What I loved the most about him was how he respected everyone equally and never shied away from helping others.

It didn’t take time before we became inseparable. We’d spend weekends exploring new restaurants, binge-watching sitcoms, and dreaming about the future.

“Har,” he’d say with a teasing grin, “if you weren’t such a good cook, I’d probably starve to death.”

A man standing in his house | Source: Midjourney

“Good thing I love feeding you,” I’d reply, laughing as he polished off yet another plate of lasagna.

Mark worked as a software developer, a job that sometimes kept him at his desk late into the night. I never minded, though. I understood his dedication and appreciated the effort he put into his career.

As for me, I was living my dream as a teacher. My students were my little rays of sunshine, and I loved every chaotic, beautiful moment of my job.

Children in a classroom | Source: Pexels

When we decided to get married, we both agreed that our wedding should be a celebration of love and fun. We wanted everyone to feel as happy as we did.

“Let’s make it the kind of wedding people will talk about for years,” Mark said one evening as we brainstormed ideas.

“Definitely,” I replied. “How about games? Fun ones that get everyone involved?”

“Perfect,” he said, his eyes lighting up. “We can have trivia or charades or something. Maybe even a karaoke battle.”

A man talking to a woman | Source: Midjourney

We even looped in my sister, Melissa, for some ideas. At the time, she didn’t seem particularly interested.

“I don’t know,” she said with a shrug. “You guys are the creative ones. Just tell me what to do, and I’ll help.”

With Melissa’s lackluster input, Mark and I continued planning the wedding of our dreams. Every detail mattered to us, from the playlist to the seating chart.

Mark was attentive to everything, from how the napkins matched the centerpieces to ensuring that the cake was perfect.

A wedding planner | Source: Pexels

“This is going to be the best day of our lives,” I told him as we finalized the guest list.

“It will,” he said, squeezing my hand. “I can’t wait to see you walk down the aisle.”

And I believed him. I believed in us. We were the perfect team, and nothing could go wrong.

Little did I know, the wedding we so lovingly planned would turn into a moment I’d wish I could forget.

An upset woman | Source: Pexels

The day of the wedding had finally arrived, and I was filled with excitement.

As I stood in front of the mirror, I couldn’t stop smiling. This was it. This was the day I’d dreamed of for so long.

When I walked into the venue, the energy was electric. Everyone seemed to be having a wonderful time, laughing, chatting, and soaking in the atmosphere we’d worked so hard to create.

Mark greeted me at the entrance with a kiss on the cheek.

A woman smiling on her big day | Source: Midjourney

“You look stunning, Har,” he said, his voice full of admiration.

“And you look dashing yourself,” I replied with a grin, taking in his crisp suit and the way his eyes sparkled.

Everything felt magical until Melissa grabbed the microphone.

“Alright, everyone!” she called out, her voice cutting through the chatter. “I have a little surprise for the happy couple! I’ve been planning this for weeks, and I promise it’s going to be so much fun!”

I looked at her with wide eyes. I hadn’t heard anything about a surprise game.

A woman at her sister’s wedding | Source: Midjourney

“Melissa, what’s this about?” I asked, walking over to her.

“You’ll see!” she said with a mischievous grin. She waved to a man in the corner, who wheeled in a small machine with wires and sensors.

“What on earth is that?” I asked, my curiosity piqued.

“It’s a lie detector!” Melissa exclaimed, beaming. “I saw this online and thought it would be a hilarious wedding game. You and Mark will answer a few fun questions while hooked up to it. Trust me, everyone’s going to love it.”

A woman talking to her sister | Source: Midjourney

I glanced at Mark, who gave me a skeptical look but shrugged.

“Why not?” he said. “Let’s give them a show.”

“That’s the spirit!” Melissa exclaimed, clapping her hands. “Come on, let’s get started.”

The technician hooked us up to the machine, and Melissa began with lighthearted questions.

“Mark,” she said with a smirk, “have you ever eaten the last slice of pizza and blamed it on Harlene?”

He laughed. “Yes,” he admitted, to a chorus of laughter from the guests.

A man on his big day | Source: Midjourney

Next, it was my turn.

“Harlene,” Melissa asked, “have you ever secretly binge-watched a show without Mark?”

“Guilty as charged,” I said, grinning as the detector beeped to confirm I was telling the truth.

The questions continued, each one sillier than the last. Guests took turns coming up with their own, like, “Have you ever lied about liking your partner’s cooking?” or “Did you ever have a crush on a celebrity while dating each other?”

The air was filled with laughter, and I thought this might actually be one of the most memorable moments of the day.

A woman looking straight ahead, smiling | Source: Midjourney

Then Uncle Sam stood up. His usually jovial face was deadly serious as he walked toward the mic.

“Now it’s my turn,” he said, his voice low and deliberate. “Mark, did you ever cheat on my niece?”

Wait, what? I thought. Where did that come from?

I stared at him in silence, while the murmurs filled the air.

Mark chuckled nervously, looking around at the stunned faces.

“That’s a ridiculous question, Uncle Sam. I don’t think I need to dignify it with an answer,” he said, trying to wave it off.

A groom talking to a man | Source: Midjourney

But Uncle Sam wasn’t smiling.

“I think you should, Mark,” he said firmly. “If you’ve got nothing to hide, what’s the harm in answering?”

I felt my heart pounding in my chest.

“Mark,” I said, trying to diffuse the tension, “it’s just a game. Let’s not ruin the mood, okay?”

Mark turned to me, his jaw tight. “Exactly. It’s just a game, and this question is out of line.”

But the look in his eyes gave me pause. There was no humor there, no easy confidence. He looked… defensive.

A groom at his wedding | Source: Midjourney

I tried to reassure myself. This was Mark, my Mark. The man I’d trusted and loved for five years. There was no way he’d cheated on me. Right?

But Uncle Sam wasn’t backing down. “Why not answer, then? If it’s absurd, prove it.”

Mark clenched his fists, his face hardening. “Because it’s insulting, that’s why. I don’t owe anyone an answer to something so ridiculous.”

I glanced around the room, noticing the growing unease among the guests. The whispers, the exchanged glances. My pulse quickened. Why was Mark reacting this way?

A woman at her wedding | Source: Midjourney

“Mark,” I said softly, reaching for his hand. “Answer it so we can move on.”

But he shook his head. “No, Harlene. I won’t dignify this with a response.”

His response told me something wasn’t right.

“Mark,” I said, my voice trembling, “if you don’t answer, I’m not sure I can go through with this wedding. I need to know there’s nothing to hide.”

He looked around and then sighed.

“Fine,” he said, glaring at Uncle Sam. “No, I have not cheated on Harlene.”

A man talking to an older man | Source: Midjourney

Uncle Sam looked at the technician. “He’s lying, isn’t it?”

The technician quickly analyzed the results and nodded. “It looks like a lie.”

The gasp from the crowd was deafening.

“What?” I whispered. How is this possible?”

Uncle Sam smiled.

“Is there anyone in this room with whom you cheated?” he asked.

Mark looked like he’d been cornered. “No,” he said flatly.

“Another lie,” the technician said promptly.

I couldn’t believe it.

“Who, Mark?” I asked. “Who did you cheat on me with?”

A bride talking to the groom | Source: Midjourney

He didn’t answer.

That’s when I noticed Melissa, my sister, shifting uncomfortably. A horrible thought crept into my mind.

“Was it her?” I asked, pointing at Melissa. “Did you cheat on me with my sister?”

Mark froze. He looked at Melissa before his gaze locked with mine.

“Tell me Mark!” I insisted. “Was it her? Melissa?”

Mark looked at the ground and said what I didn’t want to hear.

“Yes,” he said.

The machine didn’t need to confirm it, but it did. Truth.

A man standing outdoors | Source: Midjourney

The silence in the room was deafening, broken only by my shaky breath. My mind raced as I stared at Mark, then at Melissa, who looked like she wanted to disappear into the floor.

Before I could even form a question, Uncle Sam cleared his throat.

“I wasn’t going to say anything today,” he began, his gaze fixed on Mark. “But I saw you two together a few weeks ago. I was at the mall, grabbing lunch, when I spotted you, Mark, holding Melissa’s hand. I thought maybe I was imagining it until I saw the way you leaned into her. The way you touched her cheek.”

A man and a woman standing in a mall | Source: Midjourney

He paused, shaking his head in disgust. “It wasn’t how a future brother-in-law behaves with his fiancée’s sister. I hoped I was wrong, but something told me I wasn’t. So, when Melissa showed up today acting nervous and twitchy, I decided it was time to find out the truth.”

His words were like knives, cutting through whatever illusion I’d been clinging to. I looked at Melissa, whose face was streaked with tears. “Why?” I whispered, barely able to speak. “You’re my sister. How could you?”

“Harlene, I…” she started, but her voice cracked, and she couldn’t finish.

A woman talking to her sister | Source: Midjourney

Then, I turned to Mark. “You didn’t just betray me. You betrayed everything we built together. How could you do this? Why?”

Mark looked away, unable to meet my eyes. “I made a mistake,” he muttered, as if that was supposed to erase the pain he’d caused.

My chest tightened, and my vision blurred with tears. I couldn’t forgive Mark. I knew cheating wasn’t just a mistake. It was a choice, and one I could never accept.

Without another word, I ripped off the wires from the lie detector and walked out, leaving behind the man I thought I knew, the sister I thought I could trust, and the wedding that would never be.

Some betrayals leave scars too deep to heal, and this was one I couldn’t ignore.

A bride running away | Source: Freepik