Common-Law Blended Families and Estate Planning in Ontario: Why the Risks Are Higher

Blended families already carry more estate planning complexity than most. Add a common-law blended family structure — where the couple is not legally married — and the default legal protections shrink considerably. In Ontario, the gap between what a married spouse automatically receives and what a common-law partner automatically receives is one of the widest in the country.

If you are in a common-law relationship with children from an earlier relationship in the picture, here is exactly where the default rules leave you exposed.

The Core Gap: No Automatic Intestacy Rights

If you die without a valid will in Ontario, only a legally married spouse has automatic inheritance rights under the intestacy rules. A common-law partner has none — regardless of how many years you lived together, how you presented as a couple, or how intertwined your finances became.

This is one of the most consequential and most commonly misunderstood points in Ontario succession law, and it hits common-law blended families especially hard: without a will, your partner could be left with nothing, while your children (from any relationship) inherit everything under the statutory formula.

No Equalization Election Either

Married spouses have a further backstop: the right to elect, within six months of death, to take an equalization payment under the Family Law Act instead of what a will or intestacy provides. That specific election belongs to a surviving married spouse. A common-law partner does not have the same statutory right to elect for equalization in the same way.

What a Common-Law Partner Can Try Instead: Dependant Support

A common-law partner who is left out entirely may be able to bring a dependant's support claim under Part V of the Succession Law Reform Act, but only if they meet that Part's specific definition — generally, continuous cohabitation of not less than three years, or a relationship of some permanence where the couple are parents of a child together. Even then, this is a claim someone has to actively bring, subject to its own time limit, not an automatic entitlement like a married spouse's preferential share.

Married Spouse vs. Common-Law Partner: The Defaults Compared

What This Means for Blended Families Specifically

Picture a common-law couple where one partner has children from an earlier relationship. If that partner dies without a will, their children inherit everything under the intestacy formula, and the surviving common-law partner receives nothing directly — no preferential share, no automatic split, no election. Their only potential path is a dependant's support claim, which is uncertain, fact-specific, and takes time to resolve. That is a considerably harder starting position than a married spouse would face in the same scenario.

What Unmarried Step-Parents Should Do Differently

• [ ] Get a will. For a common-law partner, a will is the primary way to guarantee anything at all — there is no statutory fallback the way there is for a married spouse.
• [ ] Update beneficiary designations on registered accounts and life insurance to name your partner directly, since these generally pass outside the estate regardless of the will or intestacy rules.
• [ ] Review how the home and other major assets are legally held — joint ownership with survivorship works differently than sole ownership passing through a will.
• [ ] Talk to a lawyer about a cohabitation agreement addressing property expectations, to sit alongside the will rather than relying on default rules that were not built with common-law partners in mind.
• [ ] Revisit the plan after any major change — a new child, a home purchase, or a shift in the relationship should all prompt a fresh look.

Frequently asked questions