You can decide many issues, such as property division and spousal support in a marriage contract. However, some things such as custody and child support cannot be legally decided before a separation. Furthermore, any provision purporting to limit a spouse’s right to possession of the matrimonial home is unenforceable under Part II of the Family Law Act. Most importantly, there is always the possibility that your agreement, no matter how well drafted, may be set aside at some future point under certain circumstances. For instance, if your marriage lasts 20 years and your spouse is ill and cannot work after the marriage is over, a court may decide that even if he or she waived the right to spousal support, it should still be provided. In Ontario a prenuptial agreement can be set aside if the agreement is unconscionable. Ontario courts have recently been more open to setting aside prenuptial agreements that they feel are substantially unfair. In Rick v. Brandsema the husband failed to make full disclosure of his assets to his mentally unstable wife, and the prenuptial agreement was held to be unconscionable and set aside. However, typically the courts uphold most contracts, especially if both spouses had competent legal advisers.