Apparently, famous Italian git Benito Mussolini was also a git to his mistress. Three hours well spent.
It appears that the film doesn't make as strong a case for this as it might have done (see this article in the Times: http://www.timesonline.co.uk/tol/news/world/article411675.ece ).
But perhaps you're already supposed to know the story before you see the film. I imagine most Italians do.