Why You Need a Postnuptial Agreement
Didn't sign a prenup? A postnuptial agreement lets married couples define their financial rights at any point during the marriage — before a crisis forces the issue.
Reviewed by
Deepa Tailor — Senior Family Lawyer, Tailor Law
"Many couples come to me after a major life event — a business launch, an inheritance, a second marriage — wishing they had addressed their financial picture sooner. A postnuptial agreement is not a sign of distrust; it is a sign of financial maturity."
30-Second Answer
A postnuptial agreement (also called a marriage contract in Ontario) is a legally binding domestic contract signed after marriage. It can define how property is divided, address spousal support, and protect business interests — all without waiting for separation. Under the Family Law Act, it is fully enforceable if both spouses had independent legal advice, made full financial disclosure, and signed voluntarily.
6 Situations Where You Need a Postnuptial Agreement
Life changes after the wedding. Your legal protections should keep up.
You Started or Acquired a Business
A business launched after marriage is marital property subject to equalization. A postnuptial agreement can ring-fence the business, define its value, and protect co-owners and employees from the fallout of a divorce.
You Received a Large Inheritance
Inheritances are excluded from equalization — unless they are used to purchase or improve the matrimonial home. A postnuptial agreement can protect inherited funds and prevent them from being swept into the marital pool.
You Are in a Second Marriage
Blended families bring complex financial obligations — children from prior relationships, existing support orders, and assets built before the marriage. A postnuptial agreement ensures your estate plan and prior commitments are protected.
One Spouse's Income Has Changed Dramatically
A major promotion, career change, or one spouse leaving the workforce to raise children can shift the financial balance significantly. A postnuptial agreement can address spousal support expectations before resentment builds.
You Are Buying a Home Together
If one spouse is contributing significantly more to the purchase price, a postnuptial agreement can document that contribution and define how equity will be divided if the marriage ends.
You Didn't Sign a Prenup
Many couples skip the prenup conversation before the wedding. A postnuptial agreement is the second chance to have that conversation — on your terms, without the pressure of an impending separation.
What Makes a Postnuptial Agreement Valid in Ontario?
Under the Family Law Act, a marriage contract (postnuptial agreement) is enforceable only if these requirements are met.
Both Spouses Must Sign in Writing
A postnuptial agreement must be in writing and signed by both parties. Verbal agreements about property division are not enforceable under the Family Law Act.
Independent Legal Advice for Each Spouse
Each spouse must have their own lawyer review the agreement independently. One lawyer cannot represent both parties. This is the most common reason agreements are later challenged.
Full Financial Disclosure
Both parties must disclose all assets, debts, income, and liabilities before signing. Concealing assets is grounds to set aside the entire agreement.
No Duress, Undue Influence, or Fraud
The agreement must be signed voluntarily. Pressure, threats, or signing under crisis conditions (e.g., the night before a separation) can invalidate the contract.
Cannot Waive Child Support
Postnuptial agreements cannot contract out of child support obligations. Any clause purporting to limit or waive child support is void and unenforceable.
What a Postnuptial Agreement Can — and Cannot — Cover
Can Cover
- How property owned before marriage is treated on separation
- How property acquired during marriage is divided
- Whether the matrimonial home is subject to equalization
- Spousal support — amount, duration, or waiver
- How a business or professional practice is valued and divided
- Treatment of inheritances and gifts received during marriage
- Pension and investment account division
- Debt allocation between spouses
- Estate planning provisions and beneficiary designations
Cannot Cover
- Child support obligations (void and unenforceable)
- Custody or parenting arrangements (courts will not be bound)
- Anything that is unconscionable or contrary to public policy
- Provisions obtained through fraud, duress, or misrepresentation
Note: Courts retain jurisdiction over children regardless of what any domestic contract says. Child support and parenting arrangements are always subject to court review.
Frequently Asked Questions
Deepa Tailor
Senior Family Lawyer
Deepa Tailor drafts and reviews marriage contracts and cohabitation agreements for couples at every stage — from newlyweds to those navigating complex second-marriage finances.
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A postnuptial agreement drafted by an experienced family lawyer gives you certainty, clarity, and peace of mind — whatever the future holds.
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