And, once you open the door to that, who can say no to threesomes, harems of 60, or even inter-species marriage?
The government, by wading into this mess, has shown that it is utterly incapable of defining marriage at all.
They are trying to turn marriage into a meaningless joke. If two men can marry, why not three men? Why not allow man and animal to marry? A man and a dog have as much business getting married as two men. Our society is really sick.