I, Jane Doe (1948)

While stationed in France during World War II, an American fighter pilot marries a French girl, but when he goes home he doesn't take her with him--because he's already married to a successful lawyer back in the U.S. The war bride follows him to the U.S. anyway, one thing leads to another, and she winds up killing him and finds herself being defended in court by the wife of the man she has just killed.