The first film that comes to mind in the romance category is Sexy Beast. This is not a date film to be sure. Dealing with a criminal underworld, the movie is often grotesque, absurd, and even disgusting as it explores the dark, sometimes demonic recesses of the psyche.
Also, Ben Kingsley almost went mad getting into the part of Don Logan, the film's antagonist.
But in spite of all its demonic elements, Sexy Beast is a love story. A husband rises to heroism to save his wife and his marriage. Sexy Beast isn't for everyone, but it is my favorite "romantic film," if we can afford some latitude to that definition.
Runner-up in the romance comedy is about the ups and downs of a crazy marriage, a movie that is both dark and funny, Two for the Road, starring Audrey Hepburn and Albert Finney.
As a teenager, my favorite romantic film was David and Lisa, but I've become somewhat jaundiced over the years and now find that movie to be too mawkish for my tastes. Between the disgust level of Sexy Beast and the melodrama of David and Lisa, Two for the Road strikes a good balance. So maybe I'll have to rethink my favorite romantic film . . .