An increasing number of unmarried partners are falling into a legal pitfall without realising it, as family law specialists highlight that cohabitation provides considerably fewer protections than most people assume.
Statistics indicate 3.5 million cohabiting households existed in Britain during 2025, establishing them as the country’s most rapidly expanding household category. Despite this, numerous individuals mistakenly believe they enjoy identical legal safeguards to those who are married.
Legal experts at SE-Solicitors note that identical preventable errors surface repeatedly when partnerships dissolve or a partner passes away, with Patrick Mulcare, Director and Head of Family Law, cautioning that most difficulties stem from assumptions rather than documented protections.
None of these errors arise from malicious intent. They result from couples believing the legal system will treat them equitably after an extended period together. However, the law will not do so unless it has been formally documented, and at that stage people encounter the emotional and financial consequences of their failure to record arrangements.
Specialists outline five legal errors exposing unmarried homeowners to danger
1. Believing duration of relationship creates automatic entitlements
Many partners continue to assume that cohabiting for sufficient time establishes a type of common law marriage granting automatic claims to property and financial support. Such a concept simply does not exist within English and Welsh law.
Petra van Dijk, Director at SE-Solicitors, notes this misunderstanding remains among the most prevalent issues she encounters. Partners frequently state they have been together in a manner equivalent to marriage for a decade, believing this carries legal weight. It does not.
She continues that she has met individuals who have devoted ten or fifteen years constructing a home and shared life, only to discover they possess no automatic entitlement to remain in that property or share its worth when the relationship concludes. The distress this discovery causes proves considerable, representing the moment when the common law marriage myth becomes an extremely costly realisation.
2. Contributing to mortgage payments lacking documented understanding
It frequently occurs that one partner provides the initial deposit while both contribute towards mortgage payments or household expenditure. Without formal documentation, such contributions do not automatically translate into defined ownership shares.
Mortgage contributions rank among the most frequent sources of conflict when unmarried couples separate. Petra cautions that when one partner purchases a property and the other relocates in and begins paying towards the mortgage, this does not automatically grant them a claim to the property, though it does establish legal ambiguity, and that ambiguity creates the conditions for expensive, protracted disagreements.
She notes such disputes can rapidly become financially burdensome. Couples have incurred substantial legal costs debating property ownership when a straightforward legal agreement at the outset would have prevented this. Rather than proceeding with a clean sale and division, they face court costs, solicitor charges and prolonged uncertainty.
3. Financing home improvements on property lacking legal ownership
Renovation expenditure can establish another expensive grey area when one partner funds improvements to a property they do not legally hold, particularly absent written documentation clarifying whether that contribution should affect the property’s valuation.
Petra warns this can leave non-owning partners vulnerable. Partners have spent tens of thousands on kitchen renovations or extensions to properties they do not legally own without establishing what they would receive in return. Without written documentation, demonstrating entitlement to a share becomes a lengthy, costly legal dispute that may not ultimately succeed.
A Declaration of Trust resolves that ambiguity and can safeguard that contribution even after the work has been completed.
4. Neglecting to revise wills following cohabitation
Under existing intestacy legislation, a surviving cohabiting partner possesses no automatic inheritance rights to their partner’s estate, regardless of how many years they have been together or whether they share a home. Numerous couples operate under the assumption that their estate will naturally transfer to their partner without ever revising their will.
The risk intensifies considerably should one partner die intestate. Lucy Gordon, Director and Head of Private Client at SE-Solicitors, notes that partners wishing their cohabitant to inherit their share of the home require an explicit will stating this. Without such documentation, the legal system determines distribution, and it will not favour the surviving partner.
Lucy explains the consequences can prove immediate for surviving partners. She has had to inform bereaved partners that the property they anticipated would naturally transfer to them has instead been distributed to children, parents or siblings. Suddenly they face grief alongside the prospect of purchasing relatives’ shares or selling the property, all because nobody documented their intentions.
5. Depending on spoken assurances rather than documented contracts
Partners frequently depend on conversations stating that they agreed the property belongs to both of them or promised to divide everything equally, rather than formal paperwork.
Such verbal assurances may seem unambiguous at the time, though Petra notes they frequently prove challenging to establish once a relationship has deteriorated.
A conversation does not constitute a legal instrument. She has worked with clients who possessed clear verbal agreements with their partners regarding property ownership, yet none of it carried any weight once the relationship ended due to insufficient evidence the discussions occurred.
When financial matters become relevant, recollections shift. What seemed like a shared arrangement five years previously transforms into two entirely contradictory accounts in court proceedings, and at that point people recognise that undocumented promises may hold no value whatsoever.
The solution proves more straightforward than most couples assume
1. A Declaration of Trust: establishing clear ownership
A Declaration of Trust documents each partner’s contribution towards the deposit, mortgage and significant works, converting that into agreed equity shares. It can be executed at purchase or established subsequently and may outline provisions should one partner wish to sell while the other does not.
Petra explains this is why a Declaration of Trust transforms informal assurances into legally recognised instruments. She observes the same pattern repeatedly where one partner contributes more, both assume this will be honoured, yet nothing gets documented. A Declaration of Trust converts what was said in the kitchen into something the legal system will actually acknowledge should the relationship end.
2. A cohabitation agreement: defining arrangements during cohabitation and separation terms
This broader agreement addresses how bills are settled, how savings and belongings are managed, and what occurs regarding the home and contents should the relationship dissolve.
A cohabitation agreement subsequently handles the broader financial situation beyond the property itself. Petra outlines how a Declaration of Trust concentrates on the property while a cohabitation agreement encompasses the wider picture of bills, savings, possessions and what transpires regarding joint accounts or debts upon separation.
A cohabitation agreement does not represent planning for failure. It establishes what fairness means while everyone maintains amicable relations, which tends to reduce rather than generate conflict.
Petra adds that without one, couples frequently discover themselves disputing not merely the property but also furniture, savings, loans and even pets, with no agreed framework to reference. It complements a Declaration of Trust, ensuring no inconsistency between the property documentation and broader financial arrangements.
3. Revised wills because cohabiting partners do not automatically inherit
Under existing intestacy provisions, a surviving cohabiting partner possesses no automatic inheritance rights should their partner die intestate.
Regarding wills, Lucy cautions that cohabiting partners should not assume legislation will automatically transfer property to them. Partners wishing their cohabitant to inherit their share of the home require a will explicitly stating this. Without it, the legal system determines distribution, and it will not favour the surviving partner.
This can coordinate with a Declaration of Trust so that the person intended to inherit corresponds with the individual recognised by ownership documentation as possessing a stake. However, a will is also required to specify what occurs with one’s share. Failing to create one represents one of the swiftest methods of converting a sudden death into a housing crisis.