*The information provided below does not constitute legal advice
Living together is an exciting step—but it also comes with important legal and financial considerations. In Ontario, a cohabitation agreement allows unmarried, cohabiting couples to clearly define their rights and responsibilities while living together. Governed by the Family Law Act, a cohabitation agreement can address how property and debts will be handled, whether spousal support will be paid if the relationship ends, and how shared expenses will be managed during the relationship.
While similar in purpose, a cohabitation agreement is not the same as a marriage contract. A marriage contract applies to couples who are married (or planning to marry), whereas a cohabitation agreement is specifically designed for couples who live together but are not legally married. If a couple with a cohabitation agreement later marries, the agreement can automatically become a marriage contract unless the parties agree otherwise.
Spousal Support
Unmarried partners can still qualify as “spouses” for the purposes of spousal support. The Family Law Act defines a spouse to include two people who are not married but have cohabited continuously for at least three years, or who are in a relationship of some permanence and are the parents of a child together. This means that even without marriage, support obligations may arise when a relationship ends.
A spouse may be entitled to support where there is a financial need, a compensatory claim arising from roles assumed during the relationship, or a contractual basis for support. Courts consider factors such as the length of the relationship, the parties’ roles and contributions, their incomes and earning capacities, and the objective of promoting self-sufficiency where reasonable. The amount and duration of support are often guided by the Spousal Support Advisory Guidelines, though these are not strictly binding.
Importantly, spouses can modify or even waive spousal support through a properly drafted cohabitation agreement. While courts generally respect such agreements, they retain the discretion to set aside or vary support provisions in limited circumstances—particularly where there was inadequate financial disclosure, one of the parties did not understand the nature or consequences of the agreement, or where enforcing the agreement would be unconscionable at the time of separation, among other grounds.
Unjust Enrichment
In Ontario, unmarried cohabiting couples are treated differently from married spouses when it comes to property division.
Under the Ontario Family Law Act, the statutory property equalization regime applies only to married spouses. When married spouses separate, they are generally entitled to an equalization of net family property—meaning the increase in each spouse’s net worth during the marriage is calculated and equalized, regardless of who holds legal title to specific assets. This is a legislated, formula-based scheme.
Cohabiting couples (often referred to as “common-law” partners), however, do not benefit from this family property regime. There is no automatic right to share in the increase in property value, no equalization calculation, and no presumption of equal division simply because the parties lived together. Ownership is typically determined by legal title.
That said, unmarried partners are not without recourse. A cohabiting partner can make a claim based on unjust enrichment; an equitable principle that may apply where one person has unfairly benefited at the expense of the other. Rather than relying on a statutory formula, these claims focus on fairness and the specific circumstances of the relationship. Courts assess whether one partner received a benefit, whether the other experienced a corresponding loss, and whether there is a legal reason that justifies the situation.
Unlike the structured equalization process available to married spouses, unjust enrichment claims are highly fact-driven and depend on the evidence in each case. This distinction highlights the importance of proactive planning. A cohabitation agreement allows unmarried couples to clearly define their property rights in advance, reducing uncertainty and the potential for costly disputes if the relationship ends.
Children
Although a cohabitation agreement can address many financial issues between the parties, there are limits when it comes to children. The Ontario Family Law Act provides that couples can outline their intentions or general principles regarding parenting in a cohabitation agreement. However, a court can disregard any provision of a cohabitation agreement respecting education, moral training, decision-making responsibility or parenting time where the provision is not in the best interests of the child.
Similarly, the Family Law Act provides that a court can disregard any provision of a cohabitation agreement respecting child support. Child support is considered the right of the child, not the parent, and any agreement that attempts to limit or eliminate child support in a manner that is inconsistent with the applicable Child Support Guidelines can be disregarded by the court.
To be legally enforceable in Ontario, a cohabitation agreement must be in writing, signed by both parties, and witnessed. Full financial disclosure and independent legal advice are strongly recommended to ensure the agreement reflects both partners’ intentions and stands up to future scrutiny.
Whether you are moving in together for the first time, purchasing property jointly, or blending families, a carefully drafted cohabitation agreement provides clarity, stability, and peace of mind—so you can focus on building your life together with confidence.
Build Your Future Together with Legal Clarity
A cohabitation agreement is not just about planning for what could go wrong. It is about creating transparency, protecting both partners, and giving your relationship a stronger legal foundation. At Gibson Tanner Rabin, our family law team helps cohabiting couples prepare clear, practical agreements that reflect their intentions, financial realities, and long-term goals.
Reach out today to discuss how a cohabitation agreement can help you move forward with confidence.
