Research suggests that couples who live together before getting married could be behind the falling divorce rate.
According to researchers, the increase in girlfriends and boyfriends cohabiting might be acting as a firewall, stopping unstable relationships deteriorating and ending in divorce years later.
Compared with those who move in only after the wedding, international studies have suggested that couples are more likely to separate if they live together first.
However, cohabitation could be seen as promoting rather than competing with marriage, according to the Office for National Statistics (ONS).
A research on marriage and cohabiting was conducted and it reported that rocky relationships were more likely to collapse before two people go down the aisle which is potentially stabilizing the divorce rate among newlyweds. There has been a decrease in recent years in the proportion of marriages ending in separation or divorce by the fifth anniversary, the report said.
Researchers have suggested that the growth of cohabitation may have played a role in the incipient decline. Their theory explained that cohabitation acted as a marital firewall, keeping out of the married population couples whose relationship is more fragile. In addition, more cohabiting couples separate without marrying, and fewer marry, than two decades ago.
However cohabitation still remains a relatively short term type of relationship. In the early 1960s when cohabitation was seen as socially deviant, less than one in 100 adults under the age of 50 co-habit, while one in six couples co-habit these days. And before cementing their relationship legally through a marriage ceremony, about 80 percent of couples today have spent time living under the same roof.
The most recent figures show that half of cohabiting couples have married each other at the tenth anniversary of moving in together, just under four in ten have separated, and slightly over one in ten are still living together as a couple.
Academics at the University of Southampton said cohabitation has become a normal part of the life course, though not yet, according to General Household Survey (GHS) figures.
61 percent of men aged 25-44 and 64 percent of women of this age had cohabited at some point in their lives in 2004-07; of those aged 45-59, 38 percent of men and 35 percent of women, had done so.
Since the 1970s the number of couples going down the aisle has dropped. Nowadays more couples delay committing to a relationship until later on in life - on average about two years later than they did in the early 1980s. And due to the increase in time spent cohabiting, they also marry an average of five years later.
If we consider marriage and cohabitation together, people reaching their early 40s recently have entered some kind of partnership almost as much as the most married generations of the 20th century, the report added.
But because of delayed entry into partnership and higher proportions separating, at any one time there are now fewer living with a married or cohabiting partner than in the recent past.