Jack London 
The Little Lady of the Big House [EPUB ebook] 
A Psychological Thriller

The story concerns a love triangle. The protagonist, Dick Forrest, is a rancher with a poetic streak (his "acorn song" recalls London's play, "The Acorn Planters"). His wife, Paula, is a vivacious, athletic, and sexually self-aware woman, who falls in love with Evan Graham, an old friend of her husband. Unable to choose between the two men, she wounds herself mortally with a rifle in what her husband is certain is a suicide. It was Jack Londons last novel to be published during his lifetime.