The results of a study commissioned by the Cooperative Legal Services and conducted by Leeds University sociologists have shown that for many couples cohabitation is a choice for life and not just a dry-run for future marriage, reports The Daily Telegraph.
The study considered data from the Office of National Statistics which show that the number of cohabiting couples with children has increased by some 290,000 in the past decade.
In the same period the number of married couples with dependent children fell by 320,000.
The statistics show that the actual number of married couples with children is still higher, but the percentage of those with children now matches those who simply cohabit.
The study highlights changing attitudes to cohabitation, with the majority of those asked believing that the most important factor for having children should be a 'committed relationship'. The proportion of those that thought marriage was important before having children was just 27%.
The motivations for cohabitation were also explored in the study. Some 30% of respondents said that cohabitation was probably a precursor to marriage, but tellingly 20% said they would never get married and 21% said that cohabitation was a good way to reduce bills.
In terms of longevity the survey shows that married couples have longer relationships than those who cohabit. However, perhaps most worrying, the survey showed that cohabiting couples believe that they have legal rights similar to those afforded to married couples.
England and Wales currently has no legislation to protect cohabiting couples, and the case law throws up several examples of difficult cases in which cohabiting couples split after many years together leaving one partner with nothing.
Christina Blacklaws is the Director of Family Law at the Co-operative Legal Services.
"For me as a lawyer the big issue here is that despite that level of acceptance, people still labour under the complete misunderstanding that if you are in an unmarried family the law is going to protect you," she told The Telegraph.