Intolerable Cruelty (2003) – snappy, intelligent edutainement, not just a romantic fast flood movie. And about divoraceous relations.
Ridendo castigat mores: laughing castigate the mores.
I tend to agree with this IMDB review, even if it may be over-enthusiastic:
Clooney and Zeta Jones at their best, 20 January 2005
Dan Da’man: Intolerable cruelty is possibly the best written romantic [...]