Three years into our childless marriage, my mother-in-law brought my husband’s pregnant mistress into our home to be cared for and that’s when I decided to ruin the family.

The first fracture in my marriage appeared the day my mother-in-law, Margaret, stepped into our modest two-story home in Ohio with a nervous young woman clinging to her arm.I had just returned from my teaching job, still wearing my navy blue cardigan and carrying stacks of ungraded papers, when Margaret’s voice cut through the air like a knife.

“Emily,” she said, her tone cold and unyielding, resting a hand on the girl’s shoulder, “this is Claire. She’s pregnant—with your husband’s child.”