What are the conceptual grounds for entitlement to spousal support?

McLachlin J., who delivered the judgment of the court, advised that there are three conceptual grounds for entitlement to spousal support: (1) compensatory; (2) contractual; and (3) non‑compensatory. Compensatory support is justified by a spouse’s contributions to the marriage and for losses sustained as a consequence of the marriage (Moge v. Moge, 1992 CanLII 25 (SCC), [1992] 3 S.C.R. 813). Non-compensatory support is premised on the mutual obligation theory of marriage. As McLachlin J. explained at para. 28 of Bracklow: The independent, clean‑break model of marriage provides the theoretical basis for compensatory spousal support. The basic social obligation model equally undergirds what may be called "non‑compensatory" support. Both models of marriage and their corresponding theories of spousal support permit individual variation by contract, and hence provide a third basis for a legal entitlement to support.