The government cannot legislate love... They may think they can, they may think their piece of paper is all you need. But if that was the case there would be no divorce.
You have your history a little backwards though. Up until 200 or so years ago marriage had little, if anything, to do with love. Marriage was a contractual situation and had nothing to do with romance. To some extent that is why you see different attitudes towards marriage in Europe. Marriage is what was done to protect (or enhance) one's wealth. "Love" is what you had a mistress for.
So what is the license for? People are having sex outside of marriage anyway... They live together for years? Is it giving your kids the fathers name? You can do that too also I believe even if you are not married. Is it having the blessing of the government? Does the government have the ability to confer the blessings of God when the government is suppose to be impartial on religious matters?
The license is to protect your assets and enable a host of other government benefits and entitlements. It has nothing to do with anything spiritual or any blessing.
As a christian, do I really need the endorsement of a non religious government entity to validate the way I feel toward another consenting adult citizen?
Nope! You sure don't. Should you die however the object of your everlasting love coud find themselves tossed out on the street and penniless though. Your religious entity does nothing to protect any marital assets and their feelings toward you might not be so loving at that point.
Your concept of marriage based on love is quaint but relatively new. Marriage existed as a government and religious institution long before romance had anything to do with it.