How same-sex couples fill out the 2010 census form -- is it really asking how we think of our relationships?

If thinking of yourself as married to your partner turned you into husband and husband or wife and wife, then we wouldn't need a marriage equality movement, right? So imagine my puzzlement to find gay organizations instructing us to fill out the 2010 census based on how we think of our relationships. The Williams Institute, to whom I turn for all things demographic about gay men and lesbians,