[50] Justices Bastarache and Arbour concluded spousal support agreements should be
given considerable weight, except: (i) where the
circumstances under which such an agreement was negotiated and executed are unsatisfactory; (ii) where there is substantial unfairness (non-compliance with the objectives of the Divorce Act) when the agreement was entered into; or (iii) where at the time an application to determine spousal support is commenced there has been a change in
circumstances not reasonably
anticipated by the parties which renders the agreement unfair (i.e., no longer in compliance with the objectives of the Divorce Act).