Sleep hit hard, and I woke up later that morning to hear Kat on the phone. It quickly became apparent she was talking to her boyfriend. I found my own phone and saw it was 10 a.m. A solid four hours of sleep would be sufficient to party until our redeye flight tonight.

"I'm so glad you're having fun, sweetie," Kat said. She saw I was awake and smiled. She was nude except for a towel wrapped around her hair. How long had she been up? I motioned her to come to me.

"What's the plan for today?" her other side of the conversation continued.

I moved my head over...