It is not an answer that politicians will like but Seattle Times columnist Danny Westneat gets it right:

I have long thought the solution to the marriage fight is to get government out of the marriage business. Let churches marry — or refuse to marry — whomever they choose. Have the state support families through civil contracts. For the most part, families are what they define themselves to be.
This is already happening, without government. For the first time in more than a century, married households now are the minority in America. In Seattle, a whopping 67 percent of households are headed by unmarried adults.

Politicians, be they republicans or democrats, and bureaucrats do not like giving up control. Indeed, it is one of their greatest failings.

This is one area where we can start removing the bonds imposed by our state and federal governments and work to make sure that current and future legislative bodies do nothing more to discriminate against whatever form of living arrangements consenting adults may choose.