I used to think the hardest part of being an aunt to newborn twins would be the exhaustion by association — the late-night calls, the emergency diaper runs, the constant background crying that followed my sister everywhere.

I was wrong.

The real shock came the night I opened the nanny cam app and saw something that made my blood run cold.

I can’t have children. Not “maybe someday.” Not “keep trying.” Just… can’t.

After years of failed treatments and quiet grief, I stopped imagining nurseries. I stopped lingering in baby aisles. I stopped saying “when.” So when my little sister got pregnant, I poured everything I had into her instead. I threw the gender reveal. Bought the crib, the stroller, the tiny duck pajamas that made me cry in the middle of Target.

“You’re going to be the best aunt ever,” she told me once, hugging me tight.

I believed her.

Our relationship had always been complicated. She had a way of bending reality until it suited her — small lies as a kid, bigger ones as an adult. But I thought motherhood might steady her.

Then Mason was born.

And for three weeks, I wasn’t allowed to hold him.

At the hospital, I stood beside her bed with flowers and home-cooked food.

“Can I hold him?” I asked, smiling.

Her grip tightened. “Not yet. It’s RSV season.”

I sanitized. I wore a mask. I waited.

Next visit? “He’s sleeping.”

Next? “He just ate.”

Three weeks passed.

Meanwhile, I saw photos online. Cousins cradling him. My mom rocking him. Even the neighbor posted about “baby cuddles.”

Just not me.

When I confronted her, she brushed me off. “I’m protecting him,” she texted.

“From me?” I wrote back.

No answer.

The following Thursday, I drove over without announcing myself. Her car was in the driveway. I knocked. No response. The door was unlocked.

Inside, the house smelled like baby lotion and damp laundry. I heard the shower upstairs.

Then I heard Mason.

That kind of cry that isn’t irritation — it’s need.

I found him alone in his bassinet, face red, fists clenched, screaming. My body moved before my mind did. I scooped him up, and the second he hit my chest, he calmed, tiny fingers gripping my shirt.

And that’s when I saw it.

A small Band-Aid on his thigh.

Not fresh-from-a-shot. Not hospital tape. Just… placed there.

The corner was peeling.

I don’t know what made me lift it. Instinct, maybe. Or the accumulation of weeks of being treated like a threat.

I peeled it back.

And my stomach dropped.

It wasn’t an injury.

It wasn’t medical.

It was a birthmark.

Distinct. Dark. Familiar.

My brain refused to say the name at first. But my heart already had.

Footsteps thundered down the stairs. My sister appeared, dripping from the shower, eyes wild. She saw Mason in my arms. She saw the lifted Band-Aid.

Her face drained of color.

“You weren’t supposed to see it,” she whispered.

“What is this?” I asked.

“Put him down,” she pleaded.

Her voice wasn’t defensive. It was terrified.

I placed Mason gently back in the bassinet, my hands shaking.

“Why did you keep me away?” I demanded. “Why am I the only one?”

She didn’t answer directly. She just stared at the mark like it might vanish if she willed it.

I left without crying. Without screaming. Just cold.

When I got home, my husband was in the kitchen, humming.

“How’s the baby?” he asked casually.

The way he said it made something inside me shift.

That night, I watched.

I watched him keep his phone face-down. I watched him jump when it buzzed. I watched him wash his hands longer than usual.

Two days later, while he showered, I did something I never imagined I would.

I pulled hair from his brush and ordered a DNA test.

I told myself I was being dramatic.

But I couldn’t live inside that question.

The results came in on a Tuesday.

I opened them in a parking lot, because I didn’t want my house to witness that moment.

The percentage blurred on the screen.

There it was.

Confirmation.

The birthmark under Mason’s Band-Aid had a reason.

The same distinctive mark my husband had carried on his thigh since I’d known him.

That night, I walked into the house and held up my phone.

His smile collapsed before I even spoke.

“I know why she wouldn’t let me hold him,” I said quietly. “Because I saw it.”

He went pale.

The truth spilled out in pieces — years of betrayal. An affair with my sister that predated her pregnancy. A baby they never planned but didn’t stop.

“I swear, it wasn’t supposed to go this way,” he said.

But it already had.

The Band-Aid wasn’t to hide a wound.

It was to hide resemblance.

My sister hadn’t been afraid of germs.

She’d been afraid of recognition.

I filed for divorce. Cut contact. Packed up the life I thought I had.

I miss Mason sometimes. That’s the part no one talks about. Loving a child who is proof of your own undoing.

But I refuse to live inside someone else’s lies.

What I saw under that Band-Aid wasn’t just a birthmark.

It was the truth.