A cohabitation agreement is a written contract that lets unmarried partners in Ontario decide who keeps the home, the savings and the debts if they separate.
Ontario’s property-sharing rules cover married spouses only. Say you live with your partner for ten years in a condo that is in their name. When you split up, the condo is still theirs.
Couples moving in together usually discuss how to split the rent and the grocery bill. Few of them talk about who keeps the condo, the savings or the car loan if the relationship ends. This guide covers what happens without an agreement, what to put in yours and what makes it hold up in court.
What Is a Cohabitation Agreement?
A cohabitation agreement is a contract two unmarried partners sign when they move in together, or at any point after. Ontario’s Family Law Act treats it as a domestic contract, and section 53 lets it deal with property, support and almost any other money matter.
Most agreements deal with:
- who owns what, including the home
- how you share bills and savings
- who is responsible for which debts
- whether one of you will pay the other support, meaning money to help them get by after a breakup
- what happens if one of you dies
- how you will handle a dispute, for example by seeing a mediator, a neutral third person, before anyone goes to court
An agreement cannot settle decision-making responsibility for your children, meaning who makes the major decisions, or parenting time, meaning which days they spend with each of you. If it sets child support below what Ontario’s child support guidelines call for, a court can order a different amount.
Cohabitation Agreement vs. Prenuptial Agreement: Key Differences
A marriage contract, which most people call a prenup, is signed by couples who are married or about to marry. Partners who live together without marrying sign a cohabitation agreement instead.
If you sign a cohabitation agreement in 2026 and marry each other in 2029, it becomes a marriage contract on your wedding day (section 53(2)), and you do not have to sign anything new.
Review it before the wedding anyway, because married spouses have rights that unmarried partners don’t, such as sharing the growth in property and special rights to the family home. An agreement written for an unmarried couple may need updating after the wedding.
For national context on these relationship choices, see our marriage statistics in Canada.
Why Do Unmarried Couples in Ontario Need a Cohabitation Agreement?
The 2021 Census found 15.7% of Ontario couples living common law, and 22.7% across Canada, according to Statistics Canada. Family figures from the 2026 Census are not out yet.
Many of these couples believe that after a few years they are “basically married,” but Ontario law does not see it that way. Time together can give you a right to ask for support. It does not give you an automatic share of your partner’s property.
An agreement matters most when:
- one of you owns a home, or you are buying one
- one of you earns much more or has more savings
- one of you has children from an earlier relationship
- one of you owns a business or expects an inheritance
- one of you plans to stay home with a baby, or work part time for a while
Without one, the partner whose name is not on the home usually has to sue to recover what they paid. See what happens when a couple separates without a cohabitation agreement.
How Does Ontario Law Treat Common-Law Relationships?
Ontario law does not treat common-law relationships the same way as marriage. The gap is widest for property and the family home. Pick the month you moved in below to see which rules already apply to you.
Are we common-law in Ontario?
This checks Ontario’s spousal support rules, which use a different timeline from income tax. Nothing you enter leaves this page.
Your answer will appear here.
General information only, not legal advice. Months you lived apart, for a job in another city or during a rough patch, may not count.
| Topic | Married | Living together, not married |
|---|---|---|
| Sharing property | When they separate, the spouse with less gets an equalization payment to even things out. | Whatever is in your name stays yours. |
| The family home | Both spouses can live there, and the owner cannot sell it without the other’s consent. | Only the owner has rights. The other partner has no special right to stay. |
| Spousal support | Either spouse can ask for support. | Either partner can ask after three years living together, or right away with a child in a lasting relationship. |
| If a partner dies without a will | The surviving spouse gets a set share under Ontario’s rules. | There is no automatic share, but a common-law partner who was being supported can ask for support from what the other leaves behind. |
| What an agreement can change | A marriage contract can change most of these, but not the rights to the family home. | A cohabitation agreement can set your own rules for property, the home and support, though a court keeps some power over support. |
Property Division
Married spouses share the growth in what they own during the marriage. When they separate, the spouse who ends up with less receives a payment to even things out. This is called equalization.
Unmarried partners do not share property this way. Each of you keeps what is in your own name.
To claim more, a partner has to prove in court that the other was unjustly enriched by what they put in, for example by paying down the other’s mortgage. These claims are slow, costly and uncertain.
The Supreme Court of Canada set out how they work in Kerr v. Baranow (2011). Read more about property division.
Spousal Support
Unmarried partners can ask for spousal support in two situations (Family Law Act, section 29):
- you lived together for at least three years in a row, or
- you are in a lasting, committed relationship (the law says “of some permanence”) and you are the parents of a child together.
Your agreement can set the amount of support, limit it or waive it entirely. A court can still overrule that part if the result would be unconscionable, meaning shockingly unfair (section 33(4)).
Inheritance Rights
If your partner dies without a will, Ontario’s rules give a married spouse a right to a share and give an unmarried partner nothing automatically.
If you lived together for three years, or have a child together, and your partner was paying your bills or had a legal duty to support you, you can ask a court for support from their estate (Succession Law Reform Act, sections 57 and 58). The estate is the money and property they leave behind. This is a support claim, not an inheritance.
A will is the simpler protection, so pair your agreement with estate planning.
If One of You Owns the Home
A home in one partner’s name stays theirs when you separate. The other partner has no right to stay in it and no share of its value, even after years of paying toward it. They can only get money back by proving unjust enrichment in court, unless a cohabitation agreement already records what each of you paid and how it comes back to you.
What happens to the home?
If you pay toward a home your partner owns, choose the third option.
Without an agreement
The home stays with the owner. The other partner has no right to stay and no share of its value, even after years of paying bills. To claim anything, they have to go to court.
With an agreement
You can agree in advance that, for example, the owner keeps the condo and the other partner gets back their mortgage payments or a set share of any rise in its value.
Without an agreement
You each own the share shown on the title. If you cannot agree on what to do after a breakup, either of you can ask a court to order the home sold. Disputes about who paid more often follow.
With an agreement
You can agree who keeps the home, what one of you pays to buy out the other, and how a bigger down payment from one of you is paid back.
Without an agreement
Paying the mortgage or a contractor does not put your name on the title. To get that money back, you have to prove in court that the owner was unfairly enriched.
With an agreement
You can write down what each of you paid and how it comes back to you, for example 25% of any rise in the home’s value.
Your own facts can change the answer, so treat this as general information.
Settle what happens to the home
When one of you owns the home, or you are buying one together, the agreement can record each partner’s share, how the down payment and mortgage payments are paid back and what each of you leaves with if you separate. Nussbaum Law prepares cohabitation agreements for a flat fee of $3,100 + HST.
When Should You Sign a Cohabitation Agreement in Ontario?
Sign before you move in if you can. At that point nobody has paid into the other’s mortgage, and talking about money is easier.
If you already live together, sign soon. Every month of shared rent, groceries and renovations adds to what you would have to untangle.
Make or update an agreement before:
- buying a home together, or moving into a home one of you owns
- having or adopting a child
- one of you leaves work or cuts back hours
- one of you receives a large inheritance or gift
- starting a business
- getting married
Leave a few weeks for each of you to read it and see your own lawyer. An agreement pushed on someone the week before a move is easier to challenge later.
What Should Be Included in a Cohabitation Agreement?
A judge cannot decide who keeps the car from a line like “we’ll split things fairly.” A good agreement names the car, the condo and the savings. Work through the checklist below with your partner before you meet a lawyer, so the first meeting is spent on your terms rather than on paperwork.
Cohabitation agreement checklist
Tick an item once it is done. Your ticks stay on this device, and you can print the list to bring to your lawyer.
Gather these papers, for each of you
Write these down
Decide together
Before you sign
Flat fee cohabitation agreement services
Flat fee for a cohabitation agreement
$3,100 + HST
This is for couples who already agree on the main terms. We act for one of you, and your partner gets their own lawyer.
Included
- A consultation with a lawyer
- Preparing your agreement from the terms you have agreed
Not included
- Your partner’s own lawyer
- Property valuations, appraisals and tax advice
- Fees charged by outside providers
- Negotiation, if you do not agree yet
A case review is free. A member of our team asks about your situation and tells you which service fits. No legal advice is given at that stage.
Creating a Cohabitation Agreement: DIY vs. Hiring a Cohabitation Lawyer
For a couple with little money or property, similar incomes and no children, a cheap online template may be a reasonable start.
The most common problems with templates are:
- you never show each other your full finances (called disclosure), one of the main reasons a court can cancel an agreement
- neither partner gets their own legal advice
- vague terms, like “the house will be split fairly”
- clauses copied from another province, where the law is different
A lawyer writes the agreement for your situation, makes sure you have both shared your full finances and explains what you are giving up. That makes it much harder to challenge later.
Our $3,100 + HST flat fee is for couples who have agreed on the terms and want a lawyer to put them into a proper agreement.
How to Make a Cohabitation Agreement Legally Binding in Ontario
Most agreements that hold up are made in five steps:
- Agree on the main terms with your partner, using the checklist above.
- Show each other your full finances, including debts.
- One lawyer writes the agreement from the terms you agreed.
- Your partner takes the draft to their own lawyer for independent legal advice.
- You both sign, and each signature is witnessed.
Will your agreement hold up?
Check your agreement against these three lists before you sign.
The law requires three things (section 55(1))
- It is in writing
- You both sign it
- Your signatures are witnessed
These make it hard to challenge
- You both give full financial disclosure: every asset, debt and source of income
- Each of you gets independent legal advice from your own lawyer, who usually signs a certificate saying so
- You both have time to read it and ask questions
- Nobody is pressured into signing
- The terms are ones you could both live with later
A court can set it aside if (section 56(4))
- One of you hid significant assets or debts
- One of you did not understand what the agreement meant
- Someone was pressured into signing, or the terms are unfair under ordinary contract rules
Years after you sign, a judge can still change support terms that leave one partner in a shockingly unfair position. A judge can also set aside any term about the children that does not serve them.
What Happens If There Is No Cohabitation Agreement?
Without an agreement, Ontario’s default rules decide. Whatever is in your name stays yours, and anything you paid for jointly can end up in front of a judge.
Suppose Priya owns a condo, and Mark moves in and pays half the mortgage for six years. When they separate, the condo is still Priya’s.
Mark can try to get some of his payments back, but only by proving in court that Priya unfairly benefited. That can take years and eat up much of what he hoped to recover.
With an agreement, they could have settled this the week Mark moved in, for example by giving him 25% of any rise in the condo’s value.
How to Modify or Cancel a Cohabitation Agreement
You can change or cancel your agreement at any point if you both sign the change in writing in front of a witness, the same way as the original (section 55(1)). The usual reasons are a new house, a new baby or a big jump in one partner’s income.
A change your partner refuses to sign has no effect, and the original agreement keeps applying.
Take it out of the drawer after each of the life events in the list above, such as a new baby or an inheritance, and once more before a wedding.
How a Cohabitation Agreement Protects Business and Personal Assets
A bakery, a dental office or an accounting practice that you own can stay yours alone if the agreement says so. The agreement can also say what happens to any growth in the business’s value while you live together.
If your partner pitches in, for example by doing the books on weekends, that help can become the basis for a claim on the business unless the agreement deals with it.
You can keep other things separate the same way, including:
- a home or investments you owned before the relationship
- an inheritance or a family gift
- a family cottage
- savings for children from an earlier relationship
Need Expert Legal Assistance?
Once the agreement is signed, a breakup does not have to mean a fight over the condo and the savings. Those questions already have answers.
Because every couple’s finances are different, consulting with a family lawyer is strongly recommended before you sign. Nussbaum Law has practised family law in Ontario since 2008, and Barry Nussbaum is a Certified Specialist in Family Law.
Barry Nussbaum, JD, MBA
Certified Specialist in Family Law
Get your cohabitation agreement started
Fill in the form on this page or call us. A member of our team will ask about your home, your savings and your timeline, then explain how the $3,100 + HST flat fee works for you.
A case review is free and gives no legal advice. You can also contact us today online.
Frequently Asked Questions About Flat Fee Cohabitation Agreements
How much does a cohabitation agreement cost in Ontario?
Nussbaum Law charges a flat $3,100 + HST to prepare a cohabitation agreement when you and your partner already agree on the main terms. That covers a consultation with one of our lawyers and drafting the agreement. Your partner pays for their own lawyer. Outside costs, like a property appraisal, are billed separately.
Is a cohabitation agreement legally binding in Ontario?
It becomes binding once it is in writing, signed by both of you and witnessed (Family Law Act, section 55(1)). A judge can still cancel it if one partner hid a debt or did not understand what they signed. Share your finances in full and see your own lawyers to avoid that.
Does a cohabitation agreement need to be notarized in Ontario?
No. Section 55(1) of the Family Law Act requires the agreement to be in writing, signed by both of you and witnessed, and it says nothing about a notary. Each partner usually signs in front of their own lawyer, who acts as the witness.
Is common-law 12 months or 3 years in Ontario?
For spousal support, Ontario family law asks for three years of living together, or less with a child in a lasting relationship. For your tax return, the Canada Revenue Agency uses 12 months, or less if you have a child together. Read more about common-law in Ontario. Neither rule gives you a share of your partner’s property.
Is my partner entitled to half my house?
Your partner gets no automatic share of a house that is only in your name, however long you have lived there together. If they paid part of the mortgage or a renovation, they can ask a court to pay them back, and a cohabitation agreement lets you settle that number before it turns into a fight.
Can we write our own cohabitation agreement?
You can, and a template costs far less than a lawyer. The trouble is that most templates never make you list your debts and savings for each other. They also skip legal advice for each partner. Either gap can give one of you grounds to challenge the agreement later. Many couples write down what they agreed and bring it to a lawyer to finish.
Can one lawyer act for both of us?
No lawyer can represent both partners on the same agreement. We act for one of you, and your partner takes the draft to their own lawyer before signing. If you want to work it out together first, the firm also offers mediation with a neutral mediator.
What if we do not agree on everything yet?
The flat fee assumes you have already decided who keeps the home, how savings are split and whether support is paid. If you are still working those out, or have not shared your finances yet, we can help through negotiation, mediation or hourly work, where the current rate is $290 to $500, depending on the lawyer and the nature of the matter.
What happens to our agreement if we get married?
Your cohabitation agreement turns into a marriage contract on your wedding day under section 53(2) of the Family Law Act, so there is nothing new to sign. Book a review a few months before the wedding anyway, because marriage gives each of you rights to the family home that an agreement written for an unmarried couple may not cover.
