Do you know why the marriage license was originally created? It didn't used to be that way. The founding fathers did not have to get government's permission to be married. However, after the Civil War there was concern by those of like attitude to yours. They believed they had a moral high ground and the ability to use government to enforce that moral high ground. And what they were morally outraged about was interracial marriage. And thus the Marriage License was born. You had to get that contract through the government and it was only held to interracial couples at first. It was a way to prevent differing races from marrying. After all, it's immoral. The SCOTUS ruled that it couldn't be held to interracial couples alone, and thus the Marriage License was extended to everyone who wished to be married (instead of the logical thing which would have been to abolish the Marriage License). In time, people learned the illogical nature of the "morally superior" cry of the racist minority wishing to impose their will upon the rest of us. Now interracial marriage is no big thing.
But like those racists who claimed to have the moral ground, those against same sex marriage work in exactly the same light. They claim to have some "morally superior" ground. They rant and rave about how we have to treat this or that as immoral. But most unforgivable of them all, they seek to enact government power against the rights and liberties of others to impress upon us all their own version of their morality. You're not the only one who lives in this country, and while it's fine to have a set of morals of your own; you may not rightfully and justly attempt to enact that moral code through government force at the expense of the rights of others. You become the thief, robbing others of their liberty. An act deftly against the principles of this Republic.