The Lady Gambles (1949)

"Once she was someone's wife ... now she's just someone's luck !"

When Joan Boothe accompanies husband-reporter David to Las Vegas, she begins gambling to pass the time while he is doing a story. Encouraged by the casino manager, she gets hooked on gambling, to the point where she "borrows" David's expense money to pursue her addiction. This finally breaks up their marriage, but David continues trying to help her.