Unmarried Households are the Majority for the First Time

The Census Bureau found that unmarried households are now the majority (via Newsalert):

For the first time ever, the percentage of married households fell below 50 percent, according to the Census Bureau, which released a brief Wednesday about families and households from the results of the 2010 Census.

The percentage of married households fell to 48.4 in 2010, down from 55.2 percent in 1990 and 51.7 percent in 2000.

“The 48 percent of husband-and-wife households in 2010 was the first time since at least 1940 that this has fallen below 50 percent,” said Daphne Lofquist, Statistician for the Fertility and Family Statistics Branch for the Census Bureau.

I wonder how much of the decline is caused by the men’s marriage strike and how much is caused by other factors? Is marriage just on the way out or is there something more at play?