The rehearsal dinner was supposed to be perfect — string lights twinkling over the beach, long tables covered in white linen, the sound of waves mixing with soft laughter and clinking glasses. My sister was glowing in a flowing white dress, already tipsy from the celebratory champagne, flitting between guests like the perfect bride-to-be. I was seated next to Torin because the seating chart had put the bridesmaid (me) beside the groom. Of course it had.

The moment I sat down, the air shifted.

Torin was in a crisp white linen shirt, sleeves rolled to his elbows, the fabric slightly damp from the humid evening air and clinging to the...