Also hat Kafka doch Felice Bauer geheiratet:

bq. Proces Kafka focuses on the real-life scenario of Kafka’s relationships with Felice Bauer (who later became his wife) and her best friend, Greta Bloch, interweaving sung letters, which reveal Kafka as self-centred, needy and vacillating, with scenes from the trial.

(‘Scenes from the trial’ is rather mystifying too)

From a review in The Observer of the opera Proces Kafka by Poul Ruders.