They cut out the Marriage tax breaks a bit over the past few years or so in the US. I know some couples that are not married because they can file seperate returns and get back more money than filing a joint married return.

But people can get married in a court house, on a ship, by an Elvis impersinator, etc. No religious cerimony involved. My wife and I got married by the Catholic church, which meant we had to pass all of their tests and take a class on Marriage, etc.