Facebook co-founder Sean Parker sent out the “save the date” cards for his wedding recently, according to the New York Post. The billionaire who was portrayed as a kind of partying bad boy in the movie The Social Network, is planning a “medieval-themed costume party” for his nuptials, the Post reveals. The save-the-date cards are actually made to look like medieval scrolls. And as one source explains, “Yes, there is a chance the wedding could end up looking like an episode of ‘Game of Thrones.’ ”

Parker and his fiancée are not the first -- nor will they be the last -- to turn a wedding into an absurd spectacle. But it is also a sign of the times. Most weddings these days are no more than elaborate and expensive costume parties (though most guests don’t have to don medieval robes). They do not symbolize commitment. They are just an excuse for putting on a show.

As the authors of the recently released report “Knot Yet” note, more and more women are having children before marriage -- if they get married at all.

By age 25, 44 percent of women have had a baby, while only 38 percent have married; by the time they turn 30, about two-thirds of American women have had a baby, typically out of wedlock. Overall, 48 percent of first births are to unmarried women, most of them in their twenties.

Indeed, there is an entirely different understanding of the purpose of marriage. The authors write:

Culturally, young adults have increasingly come to see marriage as a “capstone” rather than a “cornerstone” -- that is, something they do after they have all their other ducks in a row, rather than a foundation for launching into adulthood and parenthood.

It is sad and strange in these weeks of hearing about the new national consensus on the importance of gay marriage that we should learn just how diminished the institution of marriage has become.