Notorious Gentleman (1945)

Vivian Kenway (Sir Rex Harrison), a young Englishman from an aristocratic background, flunks out of Oxford, and decides to use his considerable charm to achieve his goal of, apparently, making dissipation his career. His derelictions include seduction, betrayals of sweethearts, family and friends, and marriage for money. All this with no signs of remorse or redemption, since his life as a completely unprincipled rake is quite enjoyable, for him, at least. Then, World War II breaks out and he is given a chance to die a heroic death for flag and country. Maybe.