God is a fairy tale use to control the weak minded. I can see it has found a home inside your very weak mind.Sin has nothing to do with the law of the land, but has everything to do with God's law. Marriage is between a man and a woman. No matter what the state of IL or the Supreme Court says about it, it is and will always be sin.
Now, one does not have to remain in this position of sinning against God; just as easy as a person chooses to engage in this activity; with God's help they can choose not to.
Your line of thought makes as much sense as trying to structure my life around puff the magic dragon.