But why is it that as a religious person you (or anyone else who cares to reply) can't separate these concepts?

I have, just not in a way that many people like. "Marriage" occures in a church. "Civil-Union" occures in a courthouse.

Did you read the quote from C.S. Lewis? I though he summed it up well. I need to get a better picture of what you are missunderstanding before I can better explain things.