Miguel Braschi (plaintiff) lived with his longtime partner Leslie Blanchard for 11 years in a rent-controlled apartment for which Blanchard was the tenant of record. Braschi and Blanchard conducted themselves and were treated by friends and family as though they were married. They shared assets and expenses and maintained joint accounts. When Blanchard fell ill, he gave Braschi power of attorney over his affairs. Braschi was the beneficiary of Blanchard’s life insurance policy and was the primary legatee of Blanchard’s estate. After Blanchard’s death, Stahl Associates Co. (Stahl) (defendant), the owner of the apartment building in which Braschi and Blanchard lived together, notified Braschi of its intent to evict him because he was not a tenant of record or a member of Blanchard’s family. Braschi sought to enjoin the eviction. After Stahl prevailed in court, Braschi appealed.