The state cannot and will not "ban gay marriage".
It is simply the case that the state does not recognize any same sex union. But two men can dress in flowing white dresses, make endless vows to each other, have a reception, get gifts and nag each other into old age.
The only thing is that the state won't issue a license to them.
Gays used to do this all the time. They were called "commitment ceremonies" before the fascists in the homosexual rights movement decided that their psychoses wouldn't be assuaged unless the state were forced by judges to officially recognize such unions as marriages.