“We need to talk,” said my mom. I was 14, and this could have meant any number of ominous things. We’d had many “talks” over the years, most of them related to my adolescent misbehavior, which arrived at 12 in particularly worrying form.

We sat together at our breakfast counter, she with a mug of Bengal spice tea, me with a glass of OJ. My mother was, and is, a very pretty woman, with bright blue eyes, skyscraper cheekbones, and an easy laugh. She sipped her tea and took a breath.

“Karen and I aren’t just friends, honey.” Her features tightened, but her eyes met mine, clear and steady. “We’re mor...