Alfred Hitchcock Presents: Don't Come Back Alive (1955)

Frank and Mildred Partridge are struggling with their finances. Frank has just landed a new job, but it won't start for another month. As they try to make light of their situation, Frank gets an idea. He persuades his wife to disappear for seven years, so that she can be declared legally dead in order to collect on their life insurance policy. She reluctantly agrees, and moves away under an assumed name. They plan to meet each other regularly, but an insurance investigator becomes suspicious of her absence, and thinks that Frank has killed her. Left almost entirely on her own, Mildred comes to prefer her new way of life.