Tender is the Night by F. Scott Fitzgerald. Really, read anything by F. Scott, but this was the novel he published a few years after Gatsby. Based on the Fitzgeralds' experiences as ex-pats in France, this follows a rich and flashy couple in the Riviera and details the wife's history of mental health with a husband who started out as her doctor. Quite autobiographical, as many of F. Scott's books were.
West of Sunset by Stewart O'Nan. This recent fiction release chronicles life for F. Scott Fitzgerald after fame had mostly passed him by, and he found himself in Hollywood, desperately trying to make money and regain name-recognition for himself with a daughter nearly grown and a wife in a mental institution.
Gatsby's Girl by Caroline Preston. A fictionalized account of the woman who rejected F. Scott in their youth, and became the basis for some of his female characters, most famously Daisy Buchanan in The Great Gatsby. It looks at what she might have thought and experienced as a former flame rises to literary stardom with a book featuring a part of their shared love story.