A new study on the group by the National Institute of Statistics and Public Studies (L’Institut national de la statistique et des études publiques (Insee)) was published this week, as reports French newspaper Le Monde.
Every year, over half a million couples (550,000) in France begin living together long-term, but neither get married nor have a civil partnership. This figure is higher than those who get married every year (240,000) and those who have civil partnerships (164,000).
Similarly, the numbers of couples living together but unmarried has increased ten times since the 1960s - from just 2.9% of couples in 1962, 2.6% in 1975, and only 6.3% in 1982. Now, this figure has risen to over a quarter of the total number of couples overall - at 26%.
These couples tend to be on average around 17 years younger than married couples - aged 38.5 on average compared to the 55.5 years on average of married people.
Those in civil partnerships - a measure that was only introduced in France in 1999 - are likely to be younger still, aged just 37.5.
Within the partnerships themselves, over 10% of unmarried couples living together had ten years between them, e.g. one partner was ten years older than the other.
Education and wealth
Those living together unmarried were likely to be slightly less-well educated; 28% had education levels lower than the Baccalaureate (high school diploma) compared to 20% of married couples and 13% of civil partners.
Similarly, unmarried couples tend to be less well-off and earn less, but they tend to be more equal, in terms of earning power, between the individuals themselves.
For example, in 47% of unmarried households, the richer partner is still likely to earn less than 60% of the total household income (a situation matched by only 33% of married couples).
Ultimately, this means that unmarried partners tend to be more equal financially and are more likely to be able to weather the financial storm individually in the event of a break up, compared to the money struggle that faces many divorcing couples.
And yet, although it is technically easier for unmarried couples to split up than it is for married partners, figures over four years - from 2012 to 2015 - showed that over 26% of cohabiting couples in 2012 had gone on to get married or have civil partnerships by 2015.
This was marginally more than the 25% who had split up by 2015, but still far less than the 50% who were still living together as an unmarried couple in 2015.
Unsurprisingly, youth had a role to play in these breakups: those who split up after three years were more likely to be in their late 20s, while those who were still living together but unmarried were more likely to be in their 40s.
Family and children
More children were affected by these perhaps-less-stable unions than those of married couples; over 210,000 children were affected by the breakups of their unmarried parents between 2011 and 2014, compared to just 150,000 children whose parents had been married and divorced.
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