How Domestic Contracts Handle Debt Brought Into a Relationship in Ontario

One of you is coming into the relationship with student loans still being paid down. The other has none. Or maybe it's a car loan, a line of credit from a rough financial stretch, or debt tied to a business one partner ran solo for years. However it shows up, debt brought into a relationship is one of the most practical things couples raise when they sit down to write a marriage contract or cohabitation agreement — and for good reason.

Ontario's property rules for couples don't treat debt the same way depending on whether you're married or living together unmarried, and neither default framework necessarily matches what a specific couple actually wants. A written domestic contract lets you decide, in plain terms, that debt one partner brought in stays that partner's own responsibility — instead of leaving it to whatever the default rules would otherwise produce.

This guide looks at how debt clauses work, why they matter differently for married and common-law couples, and what a well-drafted one actually covers.

Why Debt Needs Its Own Clause

Couples often assume that "what's mine is mine" applies automatically to debt the way it might feel intuitively fair. It doesn't, by default, apply cleanly in either legal framework:

• For married couples, Ontario's equalization scheme under the Family Law Act looks at the growth in each spouse's net worth during the marriage — broadly, what you had going in versus what you have, or owe, at separation. Pre-relationship debt already factors into that starting calculation, but the general formula doesn't necessarily match a couple's intentions about a specific debt, especially if one partner pays it down using income the couple otherwise treats as shared.
• For common-law (unmarried) couples, there's no equivalent equalization scheme at all under the Family Law Act, regardless of how long the couple lived together. Property and debt disputes for unmarried partners fall back on general legal doctrines like trust claims — a different, and generally less predictable, path than equalization.

A written clause replaces that uncertainty with an answer both partners agreed to in advance.

Married Couples: Debt and the Default Equalization Framework

If you're married and separate without a contract, pre-relationship debt is accounted for in the equalization calculation in a general sense — but the calculation is formula-driven and doesn't ask "whose fault is this debt" or "who benefited from it." A marriage contract lets you go further than the default formula by naming a specific debt, confirming who is responsible for repaying it, and stating whether payments made toward it during the marriage should affect the numbers at all.

Common-Law Couples: Why a Cohabitation Agreement Carries More Weight

Because unmarried partners in Ontario get no automatic equalization right, a cohabitation agreement's debt clause often isn't just fine-tuning a background rule — for many couples, it's the only clear agreement governing how debt, and property generally, will be handled if the relationship ends. Without one, resolving a debt dispute after a common-law breakup can mean each partner separately trying to prove a trust or contribution-based claim, which is a slower and less certain process than pointing to a signed agreement.

What a Solid Debt Clause Covers

1. Names the specific debts each partner is bringing in — lender, approximate nature of the debt, and confirmation it belongs to that partner alone
2. Addresses joint debt taken on during the relationship separately from pre-relationship debt, so the two categories aren't blurred later
3. States what happens if joint income pays down pre-relationship debt — for example, whether that changes anything about how the debt is treated
4. Covers what happens to debt tied to an asset, such as a car loan or a mortgage the couple later shares
5. Sets an update mechanism for debts that are refinanced, consolidated, or paid off and replaced with new ones

Common Mistakes Couples Make

• [ ] Naming "my debt" generally instead of identifying specific accounts and amounts owed at signing
• [ ] Ignoring what happens once joint funds start touching a pre-relationship debt
• [ ] Never updating the agreement after a major refinance or new joint debt
• [ ] Assuming a verbal understanding between partners will hold the same weight as a signed, witnessed contract
• [ ] Treating the clause as a one-way protection instead of addressing both partners' pre-relationship debt fairly

Frequently asked questions