Impact(1949) Brian Donlevy and Ella Raines.

Powerhouse millionaire industrialist Walter Williams gets his board of directors to bend to his will without ever breaking a sweat. He has a beautiful young wife, Irene, whom he dotes on, and a seemingly perfect life together in San Francisco. Walt has business in Denver, and Irene accepts his invitation to come along, turning the scenic ride over the mountains via Lake Tahoe into a mini-vacation. At the last moment, she feigns illness, then asks him to instead give a ride to her poor cousin hitchhiking his way home to Evanston, Illinois. The “cousin“ is actually her lover, Jim Torrence, masquerading as “Jim Burns”.