What is the test for an unjust enrichment claim in a matrimonial relationship?

The principles of unjust enrichment claims in the context of matrimonial or marriage-like relationships are well-known. Where one party to a relationship enriches the other, and suffers a corresponding deprivation, then in the absence of a juristic reason for the enrichment the recipient of the enrichment may be liable for damages. In a family setting, the provision of services for the benefit of one’s partner may be seen as being for the benefit of the parties’ relationship and the family as a whole. The fact of the parties’ relationship may create a “juristic reason” for the court to find that the enrichment was not unjust; see Peter v. Beblow, 1993 CanLII 126 (SCC), [1993] 1 S.C.R. 980 at 990, per McLachlin J., as she then was. On the other hand, as noted by Cory J. in that same case, at 1014, when a relationship is based on mutual trust and confidence, it may give rise to mutual rights and obligations: In those circumstances, there is strong presumption that the services provided by one party will not be used solely to enrich the other. Both the reasonable expectations of the parties and equity will require that upon the termination of the relationship, the parties will receive an appropriate compensation based on the contribution each has made to the relationship.