Deadly doubt.

A husband begins to doubt his young wife's behavior, to the point that he suspects that there is a relationship between his wife and his loyal friend. He begins to monitor his wife's behavior until he finds evidence confirming that there is a relationship between his wife and his friend. After a while, he stumbles upon evidence that supports his suspicion, he plots a crime against them so that he can get rid of his wife after finding evidence that incriminates her.