When my husband came home saying he’d crashed his boss’s car and owed $8,000 or risked losing his job, I didn’t hesitate. The money I’d inherited from my late grandmother was meant for emergencies, and I believed saving his career counted as one. I transferred every dollar without asking questions because that’s what spouses do when they trust each other completely.

A week later, while borrowing his laptop to print a recipe, I found hotel and airline confirmations for Miami. Two names appeared on the reservation—his and our next-door neighbor’s. My heart sank. Then I noticed the total cost, and everything suddenly made sense…