Unearthly Stranger (1963)

Unearthly Stranger (1963) Dr. Mark Davidson (John Neville), government scientist, meets a mysterious woman and is married quickly. He knows little of her past. His government superiors want to know more about his wife and certain strange attributes that point towards his wife more than she appears. But it turns out she actually does love her husband scientist, and her superiors set it to kill them both.