When Derek suggested we live apart for a month to "reignite our relationship," I thought it was one of those modern trends couples try when they're struggling but don't want to admit it.

He spun it like a grand idea, claiming it would help us reconnect and appreciate each other more.

"You'll see," he said, grinning over his coffee one morning. "It'll be like dating all over again. You'll miss me. I'll miss you. And when the month's over, it'll be like a fresh start."

I didn't love the idea. What wife would? But Derek was insistent. He seemed so sure this was for the best, so I packed a bag, moved into a short-term rental across town, and told myself it would be fine.

The first week was awkward and lonely.

Derek barely called or texted but chalked it up to the fact that he was "enjoying the space" and focused on staying busy.

I even started looking forward to what he'd called "our big reunion, Lisa."

One day, I invited my sister, Penelope, over.

"Are you sure about this, Lisa?" she asked as she poured herself a glass of wine. "I mean, it's a bit sketchy."

"I know," I agreed, putting together a charcuterie board. "But whenever I showed any resistance, Derek would lose his mind. So, I figured that it was something he needed to do."

"Yeah, I get that," she said. "But something isn't right about this, sis. I'd watch Derek carefully, if I were you."

I have to admit, she was right. And I felt the same way. What good reason would Derek have to actually want us to be separated?

Then, one quiet Saturday evening, my phone rang.

"Lisa," Mary's voice crackled through the line, low and urgent. "You need to come home. Right now. I saw a woman in your house. I can't see much, but I saw a silhouette through the window."

I put the knife I was using for chopping vegetables down and shook my head clear.

Mary was my neighbor and wasn't the type to overreact.

"What? Really!?"

The air felt like it had been knocked out of my lungs.

A woman? In our house?

My mind immediately jumped to the worst-case scenario:

Derek had moved someone else in. A mistress.

Then again, it could've been something else. A break-in, maybe, or Sheila, Derek's mother.