The obsession is not the only odd thing about this film. Use of hormones and purposefully orchestrated adultery opportunities is order to stimulate sex drive. In other words, our protagonist is turned on by his wife's interest in another man and proceeds to stage increasingly elaborate situations to encourage her and the other man's interest in each other. This other man is conveniently dating their daughter. An old fashioned answer from before the time of Viagra to a centuries old problem, confirming the maxim that "we want what we can't have"? So far, all this is pretty faithful to the source material, the novel "The Key" by Tanizaki.
Alas, our director oddly makes the incomprehensible decision to add a character and extra plot twist. An old maid named Hanna whose presence in the household and therefore random scenes is clunky and out of place, her never fully explained bitterness with the family, a deus ex machina switching of cleaner and poison attributed to her being color blind, and you have this mess of an adaptation of a perfectly good novel.
Persistent eerie soundtrack, overly expensive and unsettling facial expressions from all four main characters, inexplicable character actions and decisions, randomly inserted voice over narration.
And to wrap it all up, a completely arbitrary ending that serves little purpose but to render the entire narrative even more implausible and to sacrifice any little emotional investment the audience had with the characters.
Why this odd, unworthy contribution to cinema garnered any awards is beyond me.
