Aaron's Rod by D.H. Lawrence

Aaron Sisson, union official in the coal mines of the English Midlands, is trapped in a stale marriage. He is also a talented amateur flautist, and after walking out on his wife and two children Aaron impusively decides to visit Italy to pursue his dream of becoming a professional musician. During his travels he encounters and befriends Rawdon Lilly, a Lawrence-like writer who nurses Aaron back to health when he is taken ill in post-war London. Recovering his health, Aaron travels to Florence where he moves in intellectual and artistic circles, arguing politics, leadership, and submission, and begins an affair with an aristocratic lady.