Exemptions for creative figures
The first figure in which this exemption was observed was Beethoven. Yet as far as I can see Beethoven's eccentric way of life harmed no one. Matters were quite different with Richard Wagner whose anti-Semitism was obsessive, and who seduced his best friend's wife, Cosima, and required her to marry him. All in the service of his art, of course.
When he settled in Munich in 1896, the Russian painter Vassily Kandinsky was accompanied by his lawful wife, who resided in their Munich apartment. A few years later he developed a relationship with a gifted pupil Gabriele Münter, and they lived together in a house in the country. The painter went back and forth between the two homes. The reaction of the Russian wife to this bigamous relationship is not known, but in the later division of their assets Gabriele suffered by having no legal status.
In 1911 the architect Frank Lloyd Wright abandoned his wife and went off to Europe with Mamah Borthwick.
Finally, the artist Ben Shahn, noted for his works exhibiting social conscience, abandoned his family to shift for themselves during the great Depression.
The trope is allied to the legend of the tortured genius, who suffers so that the rest of us may be enlightened. Key examples from the nineteenth century are Vincent van Gogh and Friedrich Nietzsche.