Rosamunde Pilcher's The Other Wife

Rebecca Kendall is blessed with beauty, talent, a splendid home, two wonderful daughters and a loving husband, Richard, who spends much of his time in Canada, where he runs a mining firm. He has kept Rebecca in the dark about two things, however: he invested everything they own in a gold mine that has yet to yield any gold; and he has a second wife, Natalie, and a five-year-old son.