“Common law partner” refers to those who are living together similar to marriage but as unmarried partners.
This is not a real legal status, regardless of how long you have been together. But many people consider those who live together unmarried as “common-law partners” when in actual fact, they are cohabitees.
As common law partners, you do not usually have many legal rights and are certainly not entitled to the same rights as married couplles, but you can formalise the arrangement by setting up a cohabitation contract.
If you live with your partner, you are cohabitees and the legal principles that apply will depend on your circumstances, but matrimonial law does not apply.