What is a “common law” relationship?

June 9, 2021 | Christopher Crisman-Cox

People often refer to themselves as being in a “common law” relationship, or being “common law” spouses, but from a legal perspective, what does that actually mean? This blog post will explore some of the key differences between a “common law” relationship and a formal marriage, focusing on the differences in the case of a separation.

Common Law Relationship

A “common law” relationship is not a technical legal term for purposes of family law. However, many people, including lawyers, may use this term in everyday conversations for convenience. Generally, what people mean in Ontario when they refer to a “common law” relationship is a couple that has been living together for at least three years in a conjugal relationship, meaning a relationship that is effectively the same as a marriage. The reason that three years is used as a cut-off is because that is when spousal support obligations kick in under Ontario law.


In contrast, a formal marriage is much more straightforward. The parties apply for and receive a marriage certificate from the state. This serves as clear proof that they are spouses. There is no requirement for the parties to live together for a certain period of time for the marriage to take effect, and, of course, many traditional couples do not live together prior to getting married.

Differences Upon Separation

In the event of a separation, there are certain key differences between a common law relationship and a marriage.

Perhaps the biggest difference is in regard to property division. Upon separation, formally married spouses are entitled to an equal division of their net family property. In this context, the term “property” is extremely broad, and includes real estate, bank accounts and investments, and any other type of property, minus debts and other liabilities.

Perhaps surprisingly, there is not a similar entitlement to property division for those in a common law relationship. Rather, the presumption for a common law relationship is that each party takes with them only whatever property is in their name. There are still certain types of claims (for example, claims for constructive trust or a joint family venture) that a party in a common law relationship may be able to make in order to obtain some type of property division, but these are often difficult and complicated, and are worth a separate article of their own. The default position is that a married couple is entitled to property division, whereas a common law couple is not.

A second difference is in regard to spousal support. Married couples are automatically considered “spouses” for purposes of spousal support. In contrast, as mentioned above, in Ontario a common law couple needs to cohabit in a conjugal relationship for three years in order to qualify as “spouses” for purposes of spousal support. In some circumstances, a common law couple may be considered to be spouses for spousal support purposes even if they are not physically living together, so long as their relationship is otherwise sufficiently similar to a marriage.

In addition, if a common law couple in Ontario has a child together, then rather than cohabiting for three years, they only need to be “cohabiting in a relationship of some permanence” in order to qualify as spouses for spousal support purposes. This is an ambiguous phrase that is interpreted by courts on a case-by-case basis.

With regard to child support, however, there is no difference between being married or not. A parent will have the same child support obligations regardless.

One other difference is with regard to getting a divorce. For a common law couple, there is no need to obtain a formal court order granting a divorce, since they were never married to begin with. In contrast, a married couple needs to obtain a divorce, or else they remain married, even if they have been separated for years.  However, there may be limitation periods as to when a common law spouse may be able to apply for division of family property or support.

If you need legal advice regarding your rights in a common law relationship, or any other family issues, please contact the Miller Thomson family law team for assistance.


This blog sets out a variety of materials relating to the law to be used for educational and non-commercial purposes only; the author(s) of this blog do not intend the blog to be a source of legal advice. Please retain and seek the advice of a lawyer and use your own good judgement before choosing to act on any information included in the blog. If you choose to rely on the materials, you do so entirely at your own risk.