There are no legal formalities, no "piece of paper" or no religious ceremony required. Since there was no "legal" marriage, there is no need to get a divorce. In fact you cannot get a divorce simply because you never married. You just go your separate ways and are free to marry at any time.

Generally common law couples must continuously cohabit for two or three years (depending on your province) before acquiring some, but not all, of the legal rights and obligations accorded married couples.

Common law relationships can not turn into legal marriages over time.

Some provinces permit the "registration" of your common law relationship which grants you most of the same rights as a married couple.
(But then "registering" is in a real sense the same as getting married isn't it, so are you no longer common law?)

No divorce is required upon separation because no marriage ever existed.

1. Division of Property: Generally each person keeps what belongs to them upon separation and is responsible for their own debts

   Common law does not give any right to equalize family property acquired during the relationship. There is a vague legal concept called "unjust enrichment" which is difficult to prove and requires a very lengthy and expensive court battle to establish. It is seldom worth the cost and trouble. . . at least under present laws

2. The Matrimonial Home: Unless you own the home you have no rights to a share in its value upon separation. In fact you could be removed from the house at any time with no notice or recourse. You are in a sense a guest in the home and little more.

   Common law relationships bestow no ownership in the "matrimonial home."

3. Support: You must have lived together for two or three years (depending on your province) to have any rights to receive (usually the woman) or obligation to pay ( usually the man) support payments after you separate. If you have a child together you may have some support rights.

   You must apply for support within 2 years of separation or you lose all rights to any support payments

4. Hidden Assets: Common law partners have no right to prevent the other party from depleting or hiding assets pending separation

5. Inheritance: Common law partners have no right to share in an estate where your partner dies without a will.

   Nor do you acquire any rights to a "fair share" of his estate if he does not leave you what you want in his will.