I'm not saying "the government should care about who gets my house, and marriage relates to that decision, and therefore marriage should be a government issue."
I'm saying "right now, today, in the real world, the government does care about who gets my house, and marriage relates to that decision, and therefore marriage is, right now, a government issue."

As I said initially:

Perhaps if the government was not involved in any issues like that, to which the social status of my husband and me were relevant, I would agree with you that our status was a purely social issue and not a government one. That might even be an improvement over the current situation. I'm not sure. But it's not the situation I'm in.