just remove government from marriage. done.
I was typing a long reply but this was my main point. Untie the benefits granted to those by government for being married and that pretty much gets govt out of it. It would be tricky and I doubt that will ever happen..
I guess I fall into the I don't give a dang if gays marry category. Doesn't affect me. Anybody looked around lately? Lots of worse things happening that really impact the community you live in.