The Evangelical says, "Live your Life Right!"
The Catholic says, "Live your life like an apology!"
The Presbyterian says, "Mind your own business, you gossipy busy-body." (I'm Presbyterian)
Now that we have that settled, you may not have a state case, but you possibly have a federal one. There was a group of Evangelicals who got into alot of hot water a few years ago for commanding their employees be evangelicals as well - convert or get out. Clear-cut case of religious discrimination. Remember, the freedom of religion clause in the constitution was not added to deal with Shinto or buddists, it was to keep Congregationalist christians from forbidding baptists to buy land in late 1700's Georgia (a fact far too many baptists conveniently forget these days.)
Look, I find myself wondering what sort of backwater hiccup of a town you are stuck in, but above all, this is both outrageous and absurd. Social mores change over time and conditions, and there is clear evidence in the Bible that God has, in the past, made allowance. The arguement that you are "living in sin" is not only outdated, it's irrelevant.
Now the bad news. You are in a truely wretched situation here. The boss in this case is a penny theocrat with ten pounds of Pompous and an ounce of power - but it's all the power to go around. Examples of his sort of blasphemy (and he will pay high for this) abound in both the bible and history. But as long as he remains big fish in his little pond, his arrogance and pride will go unchallenged.
Bail out. It truely is all you can do. If you stay, it will not end here.
And in your prayers, forget asking for forgiveness on this. Ask what David did - "Deliver me from the hands of mine enemies."
TM