Although this comic story of a wife's suspicions about her husband's fidelity is probably the weakest of the three, the idea behind Trilogy - three overlapping stories occurring simultaneously involving the same characters - makes the whole a unique and brilliant experiment that is much much greater than the sum of its parts.
In each film scenes are revisited but seen from another point of view. So what seems comic in this second film of the trilogy - a surprise birthday party for the husband, is the social background scene of a thriller in the first, and a psychological minefield for a detective and his wife in the third. The point being made throughout is that we never really know what is going on in other peoples lives and minds even if we have been friends or have been married to them for over 20 years.