The Dark Road.

Jim Morrison is an English army officer who comes from a very old and prominent family. He marries the ravishingly beautiful but unscrupulous Cleo, who has no qualms about using her sexual allure to get the luxuries her husband can't provide. When Jim is sent off to war, Cleo embarks on a series of affairs, one of which results in her becoming the love slave of a German spy, the very spy that her husband has been assigned to track down.