Chrissy Spivey and John Richie with their daughter and Ms. Spivey’s mother, Annie Spivey, in Brooklyn. Graham Dickie for The New York Times

When Crissy Spivey bought herself a large one-bedroom, one-bath co-op in Brooklyn’s Ditmas Park neighborhood in 2018, she had all the space she needed. Shortly before she closed, she met John Richie, who had just moved to New York from New Orleans. Before long, he joined her in the apartment.