How does Tristan use Richard Wagner’s opera Tristan und Isolde?

In Thomas Mann’s 1903 novella Tristan, the opera Tristan und Isolde by Richard Wagner serves as a catalyst for the protagonist’s emotional and physical decline.1

The eccentric writer Detlev Spinell uses the music to manipulate Gabriele, the tubercular wife of a businessman, by encouraging her to reconnect with her long-suppressed talent as a pianist. When Gabriele performs a selection from Wagner’s opera for him, the experience leaves both characters in a state of intense, shared rapture.1

Mann employs this musical encounter as an ironic reworking of the Tristan and Isolde legend. While the opera represents a grand, tragic romance, the novella portrays the "Tristan" figure, Spinell, as unheroic and overwrought. Ultimately, the emotional stimulation provided by the music proves dangerous for Gabriele, triggering a relapse in her health and highlighting the contrast between the aesthetic idealism of the artist and the reality of her domestic life.1