An Affair (1998)

Seo-hyun is an ordinary housewife in her late thirties with a ten year-old son and a successful architect husband. For Seo-hyun, life is a series of banal routines, but she is well provided with upper class comforts. Her sheltered life is suddenly threatened with the appearance of U-in, her much younger sister's attractive new fiance. U-in approaches Seo-hyun and attraction evolves into a passionate affair. Seo-hyun is aware that falling for the younger man will destroy her and her family, but she cannot help herself and the new feelings that are stirring within...