When two people live together without being legally married or in a civil partnership, there is often an assumption that their legal position is similar to that of a married couple – especially when they share a home, make joint purchases or contribute to mortgage payments and household bills. In reality, the law treats unmarried partners very differently.

To avoid uncertainty about who owns what or what happens if the relationship breaks down, many couples choose to formalise their arrangements with a cohabitation agreement. But how much legal weight does this type of agreement actually carry - and are cohabitation agreements legally binding under UK law?

In this blog, the family law team at Clough & Willis explains how cohabitation agreements work, what makes them enforceable, and how they can affect your legal rights as an unmarried couple.

What is a cohabitation agreement?

A cohabitation agreement is a written agreement between two people who live together as a couple but are not legally married or in a civil partnership. It sets out each person’s rights and responsibilities in relation to property, assets, debts, and ongoing financial arrangements.

An agreement may detail:

• Who owns the home or holds a beneficial interest in it, whether the property was bought together or is legally owned by one partner.
• How contributions towards mortgage payments, household bills or other shared expenses will be treated.
• What happens to bank accounts, furniture and other assets acquired during the relationship.
• Financial provision or rights if the relationship changes or one partner dies.

The purpose of the agreement is to reduce the risk of disputes - especially in situations where only one partner is the legal owner of the property or where the financial circumstances of each person are very different.

Are cohabitation agreements legally binding in the UK?

Under the law in England and Wales, a cohabitation agreement can be legally binding if it meets the criteria of a valid contract. That means both parties must:

• Enter into the agreement freely and voluntarily, without pressure or undue influence.
• Provide full and honest financial disclosure.
• Execute the agreement properly by signing and dating it in writing.
• Seek independent legal advice (or at least obtain separate legal advice) before signing.

Where these steps have been followed, courts are generally willing to uphold the agreement - particularly if it is clear, detailed and reflects the couple’s joint intentions at the time it was signed. It is not enough for the agreement to exist informally. Without clear documentation, courts will likely not enforce the arrangement, and outcomes can become unpredictable - especially if partners are on unequal financial footing.

What makes a cohabitation agreement enforceable?

A cohabitation agreement is more likely to be enforced by the court when:

• It has been prepared with the benefit of specialist legal advice.
• Each party has had the opportunity to seek independent legal advice and raise any concerns before signing.
• The terms are fair and proportionate in view of each party’s financial circumstances, financial commitments, and contributions to property ownership.
• It was not signed under pressure or as a condition of moving in together.
• The document is kept up to date - particularly after significant life changes such as children, inheritances or large purchases.

If challenged, the court may examine the fairness of the agreement and the process used to create it. Where those involved obtained separate legal advice, courts are more likely to view the agreement as a valid contract, especially if both parties were informed of its legal consequences.

Who should consider a cohabitation agreement?

Cohabitation agreements are particularly relevant for:

• Unmarried couples purchasing property together or living in a home legally owned by one partner.
• Couples sharing bank accounts, making joint purchases or contributing to mortgage payments or renovations.
• Partners with children from a previous relationship who want to protect property owned prior to moving in.
• Those entering a pre-civil partnership agreement or planning to live together long term without becoming civil partners.
• Couples who want to define what happens if the relationship breaks down, or how to divide assets if one partner dies.

Without an agreement, disputes often turn on vague claims about joint intentions or financial contributions made without a clear understanding of the legal consequences. A written agreement can reduce uncertainty and prevent the need for expensive court proceedings in the future.

Do cohabiting couples have the same legal rights as married couples?

Cohabiting partners do not have the same legal status or rights as married couples or civil partners - regardless of how long they have lived together. There is no such thing as a common law marriage under the law in England and Wales.

Without a cohabitation agreement, many couples are surprised to find they are not legally entitled to a share of the home, savings or other assets after separation - even if they contributed financially. A court will not assume shared ownership or equal rights simply because a couple lived together or shared bills. This is why seeking professional advice and putting a legal document in place is so important for anyone cohabiting - or considering cohabiting - with a partner.

Why seek legal advice?

Cohabitation law touches on multiple areas of family law, property law and contract principles. The law around who owns what and how those rights can be enforced is rarely straightforward. Without a formal agreement, one party can easily be left without protection after a relationship breakdown.

Our family law specialists at Clough & Willis can:

• Draft clear, bespoke cohabitation agreements that reflect your exact circumstances.
• Review existing agreements to make sure they still meet your needs.
• Advise on your rights in disputes involving joint owners, a partner's property or beneficial interest claims.
• Support you during separation, particularly if there is no agreement in place or if the other party refuses to honour it.

Whether you are planning to move in together or are already cohabiting, we recommend seeking legal advice before formalising any financial arrangements or buying property. Early advice can protect both parties and reduce the likelihood of future conflict.