In 1902 Vivien became involved with the immensely wealthy Baroness Hélène van Zuylen, one of the Paris Rothschilds. Though a lesbian, Zuylen was married and the mother of two sons. Zuylen provided much-needed emotional support and stability. Zuylen's social position did not allow for a public relationship, but she and Vivien often travelled together and continued a discreet affair for a number of years. In letters to her confidant, the French journalist and Classical scholar Jean Charles-Brun, Vivien considered herself married to the Baroness. She may have published poetry and prose in collaboration with Zuylen under a pseudonym, Paule Riversdale. The true attribution of these works is uncertain, however; some scholars believe they were written solely by Vivien. Even certain books published under Zuylen's name may be, in fact, Vivien's work.
While still with Zuylen, Vivien received a letter from a mysterious admirer in Istanbul, Kérimé Turkhan Pasha, the wife of a Turkish diplomat. This launched an intensely passionate correspondence, followed by brief clandestine encounters. Kérimé, who was French-educated and cultivated, nevertheless lived according to Islamic tradition. Isolated and veiled, she could neither travel freely nor leave her husband. Meanwhile, Vivien would not give up the Baroness de Zuylen. In 1907 Zuylen abruptly left Vivien for another woman, which quickly fuelled gossip within the lesbian coterie of Paris. Deeply shocked and humiliated, Vivien fled to Japan and Hawaii with her mother, becoming seriously ill on the voyage.