“When a contract is filed under s. 35(1) [of the Family Law Act], it is open to a party who wishes to challenge enforcement or an application to vary to raise issues relating to the validity or enforceability of the contract before the court. Where choice of law issues are involved, the validity or enforceability of the contract will be determined according to the law mandated by the choice of law rules in s. 58. Contrary to the father’s submission, s. 35(2) does not provide that a domestic contract containing a provision for support is automatically deemed to be a court order in all circumstances, regardless of its terms. Section 35 simply provides a summary procedure which enables a party to file a contract with the court and to seek enforcement or variation of a provision as if that provision were an order of the court. This procedure allows parties to take advantage of a variety of statutory processes designed to facilitate recovery of support and maintenance payments.
There is nothing in s. 35 that prevents a party responding to enforcement or an application to vary from raising arguments with the court that the contract filed under s. 35(1) is not valid or enforceable. Indeed, it would not make sense that the mere filing of a contract that is invalid or unenforceable would have such an effect.”