MPs want 3.4 million cohabiting couples to have the same financial rights as those who are married.
The plan is to protect one partner from being thrown on the streets with nothing if they break up or one dies and the home is not jointly owned.
And it would mean two people who have chosen to live together rather than marry or enter a civil partnership would have to split property 50-50 just as divorcing couples must do.
MPs on the powerful Commons Women and Equalities Committee are looking into what legal mechanisms are needed to treat cohabiting couples the same as married ones.
Tory chair Caroline Nokes told the Sunday Mirror: “It is surprising they do not share the same legal rights as others given that cohabitation is now the fastest growing family unit.”
The committee will also look at what happens abroad to see if lessons can be learned there.
The end result could be a statutory definition of living together for the first time.
Only a cohabiting couple jointly owning a property will split the sale proceeds equally.
All the money goes to one person if the home is in their sole name. And a cohabiting partner has no right to the lease of private or social rented homes if the other leaves or dies unless it is in both names, and no claim on the other’s pension.
When married couples divorce the needs of children take priority so their main carer may get a bigger slice of the cake.
Solicitor Hannah Gumbrill-Ward of law firm Winckworth Sherwood, said: “Lockdowns have not only resulted in cancelled weddings but also in people deciding to move in together sooner than planned. This makes the committee’s work all the more important.”
Juliet Harvey of campaign group Resolution added: “This is not to diminish the status of marriage, but to provide some legal rights to the millions of people currently cohabiting, many of whom incorrectly believe that they enjoy a mythical ‘common-law marriage’ status.”
One in five couples live together without getting hitched or being in civil partnerships.