Think Your Cohabitation Agreement Will Hold Up? 5 Lessons from Recent Ontario Cases

You signed an agreement. You got a lawyer. You both initialled every page. So, you're protected — right? Maybe. Maybe not.

A cohabitation agreement can be one of the most effective tools for protecting both partners' financial interests. Recent Ontario cases, however, show that enforceability depends on more than the words on the page. Courts are increasingly scrutinizing how agreements were negotiated, whether the parties understood them, and whether the process was fair.

This blog will review recent Ontario case law and identify five key lessons that can help common-law partners understand when cohabitation agreements are likely to be upheld and where they may be vulnerable to challenge.

Why Cohabitation Agreements Matter More Than Ever

Nearly one-quarter of Canadian couples are choosing to live together without marrying. As a result, people are becoming more aware of an important reality: common-law partners do not automatically have the same rights as married spouses.

A cohabitation agreement allows couples to proactively define their rights and obligations and establish clear expectations about their financial and property arrangements.

Ontario's Family Law Act specifically authorizes these agreements [Family Law Act, R.S.O. 1990, c. F.3, s. 53(1)]. They can address ownership and division of property, support obligations, and any other matter in the settlement of the parties' affairs. If the parties later marry, the agreement automatically becomes a marriage contract [Family Law Act, s. 53(2)].

Simple enough in theory. In practice, it's anything but.

What Can Put a Cohabitation Agreement at Risk?

Many people assume that once an agreement is signed, the matter is settled. That's not how the law works.

Under section 56(4) of the Family Law Act, courts can set aside a domestic contract in certain circumstances, including where there was a failure to disclose significant assets, where a party did not understand the nature or consequences of the agreement, or where other principles of contract law apply.

From a practical perspective, however, courts often focus on a handful of recurring questions:

• Did both parties fully disclose their financial circumstances?

• Did each person understand what they were signing?

• Was the language clear and precise?

• Did both parties receive meaningful independent legal advice?

• Does enforcing the agreement still produce a fair result?

Recent decisions suggest that how a court answers those questions can make all the difference.

Lesson #1: DIY Agreements Can Create Expensive Problems

Some couples use internet templates and draft agreements themselves in an effort to save money. That approach can become very expensive later.

In El Rassi-Wight v. Arnold, 2024 ONCA 2, the parties prepared their own cohabitation agreement without lawyers. The document contained vague language, including references to "all rights" and "and so on." One party also did not understand key concepts used in the agreement, including the meaning of "equity."

The Ontario Court of Appeal found that the agreement was too unclear to properly interpret and ultimately set it aside.

The lesson is not that every self-prepared agreement will fail. Rather, courts need to understand exactly what the parties intended when they signed. When important terms are vague or poorly drafted, the agreement may not provide the certainty either partner thought they were getting.

Clarity matters.

Lesson #2: Strong Agreements Are Built to Handle Future Change

A well-drafted cohabitation agreement does more than address today's circumstances. It anticipates the possibility that careers, health, income, and family responsibilities may look very different years later.

In Garson v. Caron, 2025 ONSC 246, the court upheld a cohabitation agreement that had been professionally drafted, supported by independent legal advice, and designed to address future contingencies, including illness and unemployment. The court described the agreement as comprehensive and intended to survive foreseeable changes in the parties' circumstances.

The strongest agreements recognize that life is unpredictable and are drafted with enough care and flexibility to remain effective as circumstances change. For couples preparing an agreement today, the lesson is simple: an agreement should be drafted not only for the circumstances that exist now, but for the circumstances that may exist years from now.

Lesson #3: A Spousal Support Waiver Is Not Always the End of the Story

Perhaps no clause in a cohabitation agreement causes more heartache than the waiver of spousal support. Couples sign these routinely, often without fully grasping what they mean ten or fifteen years down the road. That is why support waivers often become the most heavily contested provisions in cohabitation agreements.

What many people don’t realize is that Ontario's Family Law Act permits courts to override a support waiver where enforcing it would create "unconscionable circumstances." The focus is not necessarily on whether the agreement seemed fair when it was signed. The question is whether enforcing it years later would produce a result that shocks the conscience.

The leading example remains Scheel v. Henkelman (2001), 52 O.R. (3d) 1 (C.A.). The parties had lived together for more than a decade. By the end of the relationship, one partner was 64 years old and living on a pension of approximately $407 per month, while the other possessed assets exceeding $2.5 million. The Court of Appeal concluded that enforcing the support waiver would be unconscionable, set the waiver aside, and ordered support. The court described the situation as one that would be “shocking to the conscience.”

To be clear, the lesson is not that support waivers are pointless. Far from it. Most are enforced. But couples should understand that courts remain concerned with preventing fundamentally unjust outcomes. A clause that appears reasonable when signed may be examined very differently if one partner later faces serious financial hardship.

More recently, Van der Ende v. Dool, 2023 ONSC 4333, demonstrated that similar concerns continue to influence courts. Despite a professionally drafted agreement and independent legal advice, the court found sufficient concerns regarding the impact of the support waiver to justify ordering interim support while the matter proceeded.

The practical takeaway is straightforward: support waivers can be powerful, but they are not guaranteed to withstand every future circumstance.

Lesson #4: Reconciliation Does Not Necessarily Cancel the Agreement

Relationships are rarely linear. Couples separate. They reconcile. Sometimes they do so more than once.

For years, there was uncertainty about what effect reconciliation might have on a cohabitation agreement.

The Ontario Court of Appeal addressed that issue in Krebs v. Cote, 2021 ONCA 467. The court held that reconciliation does not automatically terminate a cohabitation agreement.

The reasoning was practical. A separation agreement exists because the parties are living apart. A cohabitation agreement exists because parties are living together. When a couple reconciles, they return to the very situation the agreement was designed to govern.

The court also recognized that a contrary rule could create incentives for strategic separations and reconciliations aimed at defeating existing agreements, a concern previously discussed in Langdon v. Langdon, 2015 MBQB 153.

At the same time, the Court of Appeal emphasized that every agreement must be interpreted according to its own terms. The parties in Krebs would have benefited from clearer language specifically addressing future separations and reconciliations.

Lesson #5: Independent Legal Advice Must Be Meaningful

Many people assume that a signed certificate of independent legal advice ends the inquiry. It does not.

In LeVan v. LeVan, the Ontario Court of Appeal examined whether the advice provided was meaningful in light of the information available to counsel, including the extent of financial disclosure. The case demonstrates that courts look beyond whether a lawyer signed a certificate and consider whether either party truly had the information necessary to make an informed decision.

The same principle applies to financial disclosure. Courts have repeatedly emphasized that people cannot meaningfully give up legal rights if they do not understand the value of what they may be surrendering. In LeVan, drawing on principles discussed in Dubin v. Dubin, the court stressed the importance of knowing what assets and liabilities are on the table before rights are waived.

Before You Sign Checklist

Before signing a cohabitation agreement:

• Exchange complete financial disclosure.

• Obtain independent legal advice.

• Ensure important terms are clearly defined.

• Consider how future events such as illness, children, or career changes could affect the agreement.

The Bottom Line

Cohabitation agreements are powerful tools. When done properly, they provide clarity, predictability, and protection for both partners. Courts have shown, particularly in recent years, that they will respect a well-crafted agreement — even one that produces an outcome that, in hindsight, one party wishes were different.

But "done properly" carries a lot of weight. The law in this area is not static. Courts are paying closer attention to the process behind these agreements — how they were negotiated, what each party understood, whether the terms were clear, and whether the advice was real. An agreement that looks solid on paper can unravel quickly if the foundation beneath it is weak.

That's worth thinking about — whether you're moving in with someone, or whether an agreement you signed years ago is about to be tested. The document itself is only part of the story. What matters just as much is everything that happened before the ink dried.

If you're thinking about moving in with a partner, negotiating a cohabitation agreement, or wondering whether an existing agreement remains enforceable, our Family Law team can help you understand your rights and protect your interests. Contact us to schedule a consultation.