The changes in BC do not mean you are considered "married". You are still common-law but the new Family Law Act applies to the relationship and you have the exact same rights, liabilities, responsibilities etc. as a couple in a legal marriage.
Each province had/has separate legislation. For example, in Alberta they have the Matrimonial Property Act (for marriages) and the Adult Interdependent Relationship Act (for common-law). The rights and responsibilities under each Act are not the same. BC has implemented new legislation to make the same rights apply to each type of relationship.
You cannot assume that CIC's definition of common-law applies to everything. You need to look at the relevant legislation and industry practice. For example:
- For Canadian income taxes it is one year (or if you have a child)
- For family law as described above it is two or three years depending on the province
- For our car insurance, to get a married discount, it was three years
- To be a "spouse" for our pension benefits, I think it was two years.
Overall for legitimate common-law couples it should make no difference but for those who are using the common-law stream to extend the relationship without the obligations of marriage they need to think twice about what they are doing.