Once upon a time, people could marry each other and create a legal relationship simply by agreeing to marry, without getting a licence from the government, the publishing of banns by the church, or having a particular kind of ceremony. Because the rights between the spouses came from principles established by the common law, these became known as common-law marriagesmon-law marriages were valid in England until the Marriage Act of 1753, better known by its full flowery name, An Act for the Better Preventing of Clandestine Marriage.
Normally I wouldn’t make a fuss about terminology like this, except that the phrase “common-law spouses” kind of suggests that there are certain rights and entitlements that a couple get from the operation of the common law, and this really isn’t the case and it hasn’t been the case for two-and-a-half centuries. What’s really important is whether people qualify as “spouses” – or as “common-law partners” or “adult interdependent partners” or whatever – under the particular law that they’re looking at.
There is no such thing as a “common-law spouse” or a “common-law marriage” in British Columbia.