Marriage (n.) is the modern form of sexual renunciation in the age of Enlightenment — the nunnery and castration replaced by a model household.
Marriage (n.) may now be the most dark and daring transgression — in Lubitsch's Design for Living a woman tries it as a dangerous experiment and flees back to two men.
Marriage (n.) can be kept up as a mere social role while adultery is 'the real thing' — until the husband must choose whether to leave his wife, and discovers the social mask means more than the private passion.
Marriage (n.) by its implicit injunction should have no love in it. Too much in love? Get married, ritualize it, and cure yourself of passion with boring daily custom.
Marriage (n.) for most couples is Bertram's night: you make love to your lawful partner while cheating in your mind — actual sex has to be sustained by a fantasmatic supplement.