Family Law Agreements in BC: Why Getting One Now Can Save You Later
Most people think of "family law agreements" as something you sign on the way out of a relationship. In reality, some of the most useful ones are signed on the way in or in the middle. In British Columbia, the Family Law Act (FLA) gives couples significant freedom to write their own rules about property, debt, and support, instead of relying on the default rules that apply automatically. Used proactively, these agreements aren't a sign of distrust; they're a practical planning tool, not unlike a will or an insurance policy.
This post walks through the four main types of family law agreements in BC: proactive agreement such as cohabitation agreements, prenuptial agreements, marriage agreements, and the objectively ‘reactive’ separation agreement, what they can do, why doing one early is often better than doing one late, and how they let you "contract out" of parts of the FLA's default scheme.
Why this matters: BC's default rules apply whether you plan for them or not
Under the FLA, if you don't have an agreement, the law fills in the gaps for you. A few defaults are worth knowing:
Common-law status arrives automatically. Two people who live together in a marriage-like relationship for two years become "spouses" under the FLA with essentially the same property and support rights and obligations as married couples even if they never intended that result. There's no ceremony that triggers this; it just happens with time and cohabitation.
Family property is generally divided equally. On separation, property and debt acquired during the relationship (and increases in the value of property brought into the relationship) are typically split 50/50, regardless of whose name is on title or who paid for what. While unequal division exists, unequal division can be one of the major sticking points between couples.
Spousal support may be owed depending on the length of the relationship, the roles each person played, and the financial impact of the relationship on each person.
None of this is bad. The default scheme is designed to be fair in the average case. But "average" doesn't describe every relationship. Blended families, business owners, inherited wealth, big income gaps, second marriages, property owned before the relationship, these are exactly the situations where the default rules can produce outcomes neither person would have chosen if asked in advance. This is where a written agreement comes in.
The agreements and how they relate to each other
BC family law recognizes several labels for these agreements, and it's easy to get confused about the differences. This is partly because the legal reality is simpler than the terminology suggests.
Cohabitation agreements
A cohabitation agreement is signed by a couple who is living together, or planning to, but is not married. It can address many things, with a few examples being:
How property and debt will be divided if the relationship ends
Whether certain assets (a home, a business, an inheritance) will be excluded from division
Spousal support, including capping it, waiving it, or setting a formula
Financial arrangements during the relationship (who pays for what, how jointly-owned property is titled, etc.)
Because common-law status kicks in automatically after two years of living together in a marriage-like relationship, a cohabitation agreement is often the only way unmarried couples can opt out of, or customize, the rules that would otherwise apply to them by default.
Prenuptial / marriage agreements
A "prenuptial agreement" is simply a marriage agreement signed before the wedding. Under the FLA, "marriage agreement" is actually the umbrella term for any agreement between spouses (married or planning to marry) dealing with property division so a prenup and a marriage agreement signed after the wedding are legally the same kind of instrument, just made at different times. They typically cover the same ground as a cohabitation agreement such as what happens to property, debt, and support if the marriage ends, and sometimes how finances are handled day-to-day.
If a couple has a cohabitation agreement and later marries, that agreement can often carry forward and function as their marriage agreement though it's worth revisiting the terms at that point, since marriage can change tax, pension, and support considerations.
These agreements are advantageous in that they come at a time where two (2) spouses are not at odds and, while the process may still come with some hard conversations, being proactive means your are not negotiating in a state of hurt and grief at the end of a relationship, meaning there is one less variable to deal with.
Separation agreements
A separation agreement is signed after a relationship (married or common-law) has ended. Rather than setting out hypothetical terms for a future breakup, it resolves the actual issues on the table: division of property and debt, parenting arrangements and time with the children, child support, and spousal support. Separation agreements common family law agreement in BC simply because people may never get around to a cohabitation or marriage agreement but the same legal principles (discussed below) apply to all three.
The practical bottom line: cohabitation agreements, prenuptial/marriage agreements, and separation agreements are all contracts that let spouses agree to something different from what the FLA would otherwise impose that is contextual to their situation and agreed to between the parties. The difference between them is really just timing (before living together, before/during marriage, or after separation) not a difference in legal character.
What it means to "contract out" of the Family Law Act
The FLA is largely a "default" regime, not a mandatory one. In practice, spouses can use an agreement to:
Exclude specific property from division for example, keeping a pre-relationship home, a business, an inheritance, or a gift entirely out of the family property pool, rather than sharing in its growth in value
Change the default 50/50 split into a different percentage, or a different method of dividing specific assets, potentially based on income or other financial variables that may be relevant
Waive, limit, cap, or set the duration of spousal support, instead of leaving it to be assessed under the Spousal Support Advisory Guidelines
Set out how debts will be allocated, including debts incurred by only one spouse
Establish rules for the relationship itself such as how expenses are shared, or how jointly acquired property will be titled
There are limits. Agreements generally cannot determine child support or the best-interests-based parenting arrangements for children in a way that binds a court. Those are always subject to the child's best interests and can be reviewed regardless of what the agreement says. And even where an agreement is permitted, it isn't bulletproof which brings us to enforceability.
Enforceability: agreements can be challenged, so process matters
BC courts take contractual freedom seriously, but section 93 of the FLA gives the BC Supreme Court authority to set aside or replace all or part of a property agreement in certain circumstances. Broadly, the court applies a two-part inquiry:
1. Was the agreement fairly made? The court can set aside an agreement if, at the time it was signed:
a spouse failed to disclose significant property, debts, or other relevant information;
a spouse took improper advantage of the other's vulnerability, including a lack of understanding of the agreement;
a spouse did not understand the nature or consequences of the agreement; or
other circumstances existed that would make a contract voidable at common law (duress, undue influence, unconscionability, etc.).
2. Even if the agreement was fairly made, is it now "significantly unfair"? Under section 93(5), a court can still intervene if the agreement's effect has become significantly unfair, considering factors such as how much time has passed since the agreement was signed, the parties' intention to achieve certainty, and how much they relied on its terms. This is a deliberately high bar. Courts have confirmed that "significantly unfair" means something more than a result you might now wish were different; it requires a marked departure from what the Act's default scheme would produce, and courts weigh that unfairness against the value of certainty and reliance. Recent BC Court of Appeal authority (Schrader v. Schrader, 2025 BCCA 50) has confirmed that a dramatic, unanticipated change in property values shortly after signing can be enough to tip an agreement into "significantly unfair" territory which is a reminder that even well-drafted agreements can be revisited by the courts if circumstances shift sharply.
What this means practically: the way an agreement is negotiated matters as much as what it says. Courts are far more likely to uphold agreements where:
both spouses gave full and honest financial disclosure;
both spouses had independent legal advice from their own lawyers (not one lawyer for both);
there was no time pressure, coercion, or ultimatum attached to signing (for example, presenting a marriage agreement the week before the wedding is a recognized risk factor);
the agreement was reviewed and updated as circumstances materially changed over the years.
This is really the strongest argument for doing an agreement proactively rather than reactively: a cohabitation or marriage agreement negotiated calmly, months in advance, with full disclosure and independent counsel on both sides, may be in a much stronger position to survive a challenge than a separation agreement rushed through during a stressful breakup, or a prenup signed in the shadow of an approaching wedding date.
The benefits of doing this proactively (rather than waiting)
Certainty and reduced conflict later. An agreement negotiated while the relationship is healthy resolves the "what ifs" in advance, which tends to be far less adversarial and far cheaper than negotiating the same issues after trust has broken down.
Protection for what you bring in. Businesses, real estate, inheritances, and pre-relationship savings can be identified and protected from the outset, rather than becoming a point of dispute (and potential litigation over valuation and tracing) years later.
Clarity for blended families and second relationships. Agreements are especially valuable where one or both spouses have children from a prior relationship, want to preserve assets for those children, or are re-partnering later in life with established assets.
Stronger legal footing. As discussed above, agreements signed early, with proper disclosure and independent legal advice, are generally more durable if ever challenged than agreements signed under time pressure or after a dispute has already started.
A framework, not just a fallback. Cohabitation and marriage agreements can also address the relationship itself and not just its potential end, such as how property will be held or how expenses will be shared, giving both partners a shared understanding from day one.
A few practical notes
There's no obligation to sign one. Nobody can force a partner to sign a cohabitation or marriage agreement, and choosing not to simply means the FLA's default rules will apply if the relationship ends.
Two years of cohabitation is the key trigger for unmarried couples, after that point, common-law spouses have essentially the same property and support rights as married spouses under the FLA, which is often the single biggest reason clients decide to formalize a cohabitation agreement before or shortly after moving in together.
A cohabitation agreement can evolve into a marriage agreement. If a cohabiting couple later marries, their existing agreement can often continue to apply, though it's good practice to review it at that point.
Get independent legal advice for both parties. This isn't just a formality; it's a protective mechanism and one of the things courts look at when deciding whether an agreement should be upheld.
Revisit agreements after major life changes. A marriage or cohabitation agreement signed 15 years ago, before children, a business sale, or a major inheritance, may no longer reflect either party's intentions and stale agreements are more vulnerable to a "significantly unfair" challenge.
Bottom line
BC's Family Law Act gives couples real flexibility to design their own rules around property, debt, and support but only if they use it. Cohabitation agreements, prenuptial/marriage agreements, and separation agreements are all versions of the same basic tool, applied at different stages of a relationship. Signing one proactively with full disclosure, independent legal advice, and enough lead time to avoid any appearance of pressure is generally the best way to make sure the agreement actually holds up if it's ever tested, and to avoid uncertainty and conflict down the road.
This article is provided for general informational purposes only and does not constitute legal advice. No legal relationship is formed by reading or relying on this content.
If you’d like to learn more about family law agrements or need guidance on a legal issue, reach out to Zachary Dallman for a free consultation. Book or contact Zachary directly at zachary@zacharydallmanlaw.ca or 778.653.6163.
Services are provided throughout the Lower Mainland, Vancouver Island, Northern British Columbia, the Kootenays and Okanagan region remotely from the comfort of your own home or in person as location permits.