Theatre Macabre (1971)

S1E17 The Husband Under the Bed

Ivan Andreevich, a man consumed by suspicion, tails his wife through the city, convinced she is meeting a lover. His hunt leads him to a dark theater box, where he mistakenly confronts a stranger in the shadows. The stranger, also a jealous husband, reveals they are both deceived by the same woman. Their shared misery turns to bitter camaraderie as they hatch a plan under the cover of night, only for Ivan to realize his own wife has been playing him all along.