Most people are fuzzy on exactly what common law marriage is.
That's not exactly how it works. The idea of common law marriage emerged in medieval England, because clerics and justices who officiated at marriages were not always able to travel to rural locations where some couples lived. No matter how many years you live together and how much fairy dust you sprinkle, you will never have a common law marriage. This gives them the same rights and responsibilities as people who got married the old-fashioned way, with a trip to City Hall and a wedding. Common law marriage isn't something to do lightly.