There is a private members bill going through the House of Lords at the moment. This will give qualifying cohabitees the right to make a claim for financial assistance and the right under the law of intestacy to inherit if their partner should die.
However, there is an opt out clause. This means that the parties can choose to be excluded from the legislation provided they have had legal advice. No doubt, if the bill is passed, a large majority of cohabitees who are aware of it will take advantage of this opt out.
Why do we need such a law? A large number of cohabitees in long term relationships are vulnerable to be left homeless and with nothing should the relationship break down. This is unfair - especially if there are children involved. However, marriage would move the unfairness over to the wealthier partner so it is not difficult to understand why cohabitation is so popular.
What is fair? Matrimonial Litigation is based upon seeking a Judge's interpretation of that. Unless the new law, if it passes, is prescriptive, as in the Child Maintenance Assessment, which will of course result in unfairness to some, then the courts will be awash with new claims. No legal aid will be available for such matters so litigants in person and delay are likely.
If you live with someone and move into their house and make no financial contribution to the purchase or capital contributions to the mortgage then at present when the relationship breaks down you have no right to remain in the house or claim a capital lump sum in order to rehouse. Some could have purchased a home in their own right but instead paid for holidays and carpets, food and entertainment, clothes furniture etc. The financial contribution they made was not towards the asset - the bricks and mortar so it is ignored when the asset is left to be divided. No share but thank you for everything you have paid for. This is relationship disadvantage.
Some move in and pay for nothing. Live off their partner for years and expect it to continue. These people will benefit from the new law also if it is passed. Obtaining fairness for some results in unfairness for others. It is a bit like vaccination - the public policy will always result in a minority of losers.
The headline cases are the women who move in, have children, run the household and then when the children are older are left with nothing when the relationship ends and their partner goes off with a younger model and begins the cycle all over again.
The law cannot legislate to assist people in making better life choices, but it can assist with resolving the financial mess such choices can result in.