Orthodox Christians can't use the word "husband" for a man "married" to another man, or "wife" for a woman "married" to another woman in good conscience, so that is going to create a lot of awkwardness for everybody. Why not let marriage traditionalists have those terms back, and let the marriage revisionists come up with terms of their own that would suit everybody?
I'm serious. This is actually a good idea. The only thing that would improve on it would be to find a new word besides "marriage" to refer to an institution reflecting gay and lesbian values and expectations instead of heterosexual ones.
But wait. That would assume that it was actually "marriage equality" rather than the mainstreaming of sodomy that was the point of this whole business, wouldn't it?