This delightful film's script is a descendant of the sort of archly witty portrayals of British upper-class life that came from the pens of Somerset Maugham and Noel Coward (one of whose songs serves as musical lead-in, and at least one of whose tunes ["Mad About the Boy" - listen for it] serves as background music to comment on the action). The atmosphere of this sort of comedy may be a bit foreign to American tastes (the whole topic of infidelity is discussed in such a civilized and gentlemanly fashion among the parties- Stiff Upper Lip and all that - where Americans would be screaming at each other and going for weaponry) but as a devotee of British drama I enjoyed the movie hugely. It's a stellar cast - everyone shines, right down to Moray Watson in the small but delicious part of the befuddled butler Sellers. Jean Simmons is especially enjoyable in her out-of-character portrayal as the outspokenly vampish Hattie. Despite opinions below to the contrary, the incomparable Cary Grant fills the part of this down-at-the-heels English Lord like old brandy fills a crystal decanter. The sumptuous setting of the baronial manor and the high production values make the film beautiful to look at, to boot. (The fact that the unfortunate Lord is forced to open his manor to paying visitors to support his lifestyle is based on the historical truth of the confiscatory tax policies imposed on the British hereditary gentry by post-WWII Labor governments; everyone is entitled to their own opinions on these policies, but be assured the film makes no political comment).
It does stretch the imagination a tad that Victor could treat the whole issue of his wife's infidelity - going on right in front of his nose - in such a dispassionate manner, but that is a characteristic of this genre. Further, Grant manages to convince us that, beneath his outer imperturability, his wife's disloyalty has pained him deeply and he could not stand to lose her.
This is a not-well-known film whose appeal might be a bit specialized, but I think it's a minor gem. And I could not omit mentioning the charming opening credits with their bevy of delightfully cavorting babies.