Executive Summary: Key Legal and Evidentiary Issues

• Former common-law partners disputed the division of jointly-held property and financial contributions made during over 20 years of cohabitation.
• Denman's counterclaim sought over $200,000 based on unjust enrichment for contributions made to properties solely owned by Lessnick and later disposed of by her.
• Central issue was whether the counterclaim was prescribed under the three-year limitation period applicable to unjust enrichment claims.
• Prescription for unjust enrichment between de facto spouses runs from the date of cessation of cohabitation, not from the date the contributions were made.
• Cohabitation ended in November 2023, rendering the counterclaim timely at the time of filing.
• Sufficient factual and legal nexus existed between the main action (end of indivision) and the counterclaim (unjust enrichment) to warrant adjudication in the same proceeding.

Background and facts

Monique Lessnick and Ronald Denman lived together as common-law partners for over 20 years before their relationship ended in November 2023. During their cohabitation, the parties jointly held certain properties, including an immovable that became the subject of the present litigation. Denman also made financial contributions to other immovables that were solely owned by Lessnick at the time and which she has since disposed of.

Following the breakdown of the relationship, Lessnick instituted proceedings before the Superior Court of Quebec (District of Labelle) seeking judicial intervention to end the indivision over certain jointly held assets, including the shared immovable, and to impose conditions governing that partition. In response, Denman filed a defence and a counterclaim seeking reimbursement of more than $200,000, representing the value of his contributions to properties that were exclusively in Lessnick's name during the relationship.

The motion to dismiss

Lessnick moved to have Denman's defence and counterclaim dismissed (séquence 15). She advanced two principal grounds. First, she argued that the counterclaim was prescribed, contending that the three-year limitation period had already expired. Second, she argued in the alternative that even if the counterclaim were not prescribed, it lacked the requisite connexity with the main action to be heard within the same proceeding, and should therefore be severed and tried separately.

The court's analysis

Justice Carole Therrien, writing for the Superior Court, dismissed the motion in its entirety.

On prescription, the court confirmed that a claim in unjust enrichment arising between former de facto spouses is subject to the standard three-year prescriptive period under Quebec civil law. Critically, the court reaffirmed the well-established principle — drawing on Benzina c. Le, 2008 QCCA 803; Lussier c. Pigeon, [2002] R.J.Q. 359 (C.A.); Roberge c. Hétu, 2020 QCCS 1427; and Droit de la famille — 221925, 2022 QCCS 4193 — that this three-year period does not begin to run from the date the financial contributions were made, but rather from the moment cohabitation ceases. Since the parties' common-law relationship ended in November 2023, the prescriptive period had not yet expired at the time Denman filed his counterclaim, and the claim was therefore timely.

On connexity, the court found that the factual and legal ties between the main action and the counterclaim were sufficiently strong to justify their adjudication within the same proceeding. The court reasoned that both claims were rooted in the same underlying reality: the parties' shared financial life over more than two decades of cohabitation. In particular, the court noted that any fair disposition of the main action — determining how the jointly held immovable should be partitioned — would necessarily require an examination of the broader financial relationship between the parties, including the contributions Denman made to properties that were solely in Lessnick's name. Severing the two proceedings would therefore risk producing an incomplete or inconsistent adjudication of the parties' overall financial entanglements.

Outcome

The court dismissed Lessnick's motion to reject the defence and counterclaim, and declined to order severance of the reconventional demand. Costs were reserved to follow the outcome of the main proceeding. The motion was decided on May 14, 2026. As this was an interlocutory ruling on a motion to dismiss rather than a final judgment on the merits, no final monetary award was made in favor of either party at this stage. The quantum of Denman's counterclaim — in excess of $200,000 — remains to be adjudicated on the merits.