Regardless of your opinion on whether marriage as a legal/civil contract should exist, who should be allowed to enter into it, and how it relates to the religious ceremony of matrimony, you can hardly argue that there isn't a huge industry that has evolved around the wedding, or that there aren't societal expectations for women to desire the product of this massive industry.
The Wedding Day is sold to women as a day for the bride to be the center of attention, where she is the star, and where all her fantasies of being a princess are to be lived out. A modern wedding can cost as much as a new Mercedes-Benz, putting the newlyweds (and/or their parents) into debt at the outset. Harried brides-to-be spend months finding the perfect dress, shoes, flowers, cake, photographer, videographer....
Women (mostly, but men also) are sold the idea that Getting Married Changes You and Is Special. That the transition should include some sort of emotional trauma to prove that you're somehow different.
With a huge industrial complex built up around what should be a simple statement that these people are committing to each other, one begins to question why to do it at all.
And don't even get me started on the diamond companies, with their campaign that "he just doesn't love you unless he spends TWO MONTHS' SALARY on your ring." Not to mention the environmental impact or the gross human rights violations they perpetuate.
[This would have been a great WoW, but I didn't see zuzu's post until this morning.]