Tinto Brass: - Voyeur (1994)

The Voyeur, based on the famous erotic novel (L'uomo che guarda) by Alberto Moravia, tells the story of Eduardo "Dodo," who in public is a professor of French literature but in private a desperately lovesick cuckold, married to the ever-more-elusive Silvia. His life shattered, he becomes an onlooker rather than a participant in life. Those around him, though, seem to be living life to the fullest: his bedridden father has a scantily clad nurse and a series of lady friends; his students have unending sexual fun, sometimes in his presence; and even the public beach has become an orgy ground. Through a series of small revelations, Dodo slowly comes to realize who his rival is. The discovery, rather than destroying his marriage, strengthens and renews it.