A simple airplane seat assignment unraveled my marriage. On a flight to visit family, I sat next to a woman who introduced herself as Clara—the name I’d often heard in conversations with my husband, Oscar, about his past. She revealed that our home was once her dream house, designed with Oscar before our marriage. Even more unsettling, she shared that Oscar still sent her tulips on their anniversary and birthday, and called her during our arguments. I was devastated. Clara seemed to pity me, but I felt betrayed. After the flight, I texted Oscar: “It’s over. Speak to Clara.” It wasn’t about what he did—it was about the trust he shattered.