Despite general perception, there is no such thing as a "common-law spouse”. If you live with your partner but are not married/civil partner your rights and obligations relating to property, children and maintenance are very different compared with couples who are. This can often lead to situations, which, in the general sense, seem very unfair.

For unmarried couples, fairness plays no part and the court simply applies rigid and complex laws which are often not fit for purpose and can lead to unexpected results. There is no obligation for unmarried couples to pay maintenance to the other if the relationship breaks down, no sharing of pensions and no entitlement to share in assets, unless it can be shown that the assets are being held on trust for the other party. 

As a consequence, many couples are entering into a cohabitation agreement setting out who owns what, how the household is to be run and what should happen if the relationship ends. Provision for children is often also included in such an agreement. If drafted properly, a cohabitation agreement can avoid expensive litigation in the future.

As this is a highly complex and extremely fact-specific area of law, it is important that you seek legal advice when contemplating moving in with your partner and certainly as soon as difficulties arise.