If you are brave enough, say the following to a family lawyer: “common-law spouses have the same rights as married couples”, I guarantee you that, before you have even had a chance to draw breath, you will have one irate legal professional on your hands.

They will point out to you that, so far as England is concerned, the concept of common-law marriages ended in 1753. Alternatively, they will hang their heads in despair. For the idea that commonlaw marriages exist and that unmarried couples who live together have the same rights as their married counterparts, is quite possibly the most dangerous family law myth.

It is important to dispel this myth, given that there are now almost three million cohabiting couples in the UK.

The law does not endow an unmarried couple with rights and responsibilities towards each other in the event of the relationship breaking down. There will be rights and responsibilities towards any children from the relationship; but as for the adults, there will usually be nothing more than a strict entitlement in property law.

Consequently, we read about cautionary tales like that of Mrs Burns who, after a 19-year cohabiting relationship which produced two children, had to walk away from the relationship with nothing because her partner owned their only asset, the family home, in his sole name.

Contrast this with divorcing couples, who not only have a wide variety of mechanisms to help achieve a fair division of the family’s finances (for example, property transfer orders, pension sharing and maintenance), but have a legal framework that encourages fairness by being flexible and by taking into account the family’s individual circumstances.

The law in this area is complex and, even with three Supreme Court judgments on this exact issue in the last six years, the position is far from clear. A far better focus is on how to avoid getting into trouble in the first place.

Even as a hardened family lawyer, I know that when a couple move into together, it is meant to be a romantic experience. No one wants to discuss property ownership, mortgage payments or what will happen when the dream turns into a nightmare. However, it is precisely these discussions, ideally held early on, which will help to avoid a couple needing to resort to the law. Here are my top three things every unmarried couple should discuss:

Joint tenants v tenants in common

When buying a home together, it is important that the couple make clear whether they are buying as joint tenants or as tenants in common. The difference is substantial.

Joint tenancy means the couple both own the whole property equally and, when one of them dies, the other will automatically inherit the other’s interest.

As tenants in common, the couple each owns a specific share of the property, which means a property does not have to held 50:50. In practice, such shares will often reflect their respective financial contributions towards the purchase price. When one of them dies, each of the couple is free to choose who inherits their share of the property.

Cohabitation agreements

Drawn up as a deed and independently witnessed, cohabitation agreements are as legally binding as any other contract and are incredibly helpful in making life a little less painful when a couple separate. A cohabitation agreement not only helps clarify financial or property issues but can deal with the day-to-day workings of living together, as well as setting out what happens if the relationship ends.

Wills and pensions

Unmarried couples must also make Wills; this is simply an imperative if the couple want each other to benefit from their assets or, in some cases, even to allow the survivor to stay in their home. Pensions are another tricky area, as some pension schemes do not pay survivors’ benefits to an unmarried partner.

What you need to know is that there’s a lot more to it than this short article has described. To avoid being a Mrs Burns though, legal advice and the correct paperwork is a necessity. Either that, or consider tying the knot.