Dad invited Jake to the family cabin weekend like it was no big deal. “The more the merrier,” he said, slapping Jake on the back while I stood in the kitchen doorway pretending to scroll my phone. My pulse was already hammering. Sharing a room with him—two twin beds pushed against opposite walls, thin wooden door that didn’t even lock properly—wasn’t an accident. I’d begged Mom to let me take the small bedroom so the “guests” could have the bigger one. She thought I was being sweet. She had no idea I planned to crawl into his bed the second everyone was asleep.

The drive up was torture. I sat...