Young, married couples who had not started a family had the happiest relationships, according to a study of British attitudes published on Monday.
The initial findings of Understanding Society, a 48.9 million pound study commissioned by the government-backed Economic and Social Research Council, showed older couples were less content than their younger counterparts, with women experiencing a greater decline in happiness than men.
Researchers discovered couples who had been together for less than five years were more likely to see their happiness blossom than those in a longer-term relationship.
The taxpayer-funded study, which is tracking 40,000 households over the next 20 years in a bid to improve understanding of people's lives and experiences, found married couples were happier than their cohabiting peers.
Relationships in which both partners had a university education were also more likely to see their happiness prosper, according to the study which says it will "map the social landscape as the country recovers from the deepest recession for 60 years."
But throwing a child into the mix is likely to disrupt the romantic idyll -- researchers found couples with pre-school children were the unhappiest, but became happier as their youngest child grew up.
According to the data, unemployment has a negative impact on the amount of satisfaction a relationship can bring a man but while income did not affect male happiness in a relationship, it proved "mildly important" for women.
Of the 1,268 young people surveyed, 60 percent declared themselves to be "completely satisfied" with their family life.
Living in single parent households was associated with lower levels of happiness for children, as was living with younger siblings. Sharing the home with fewer other children was found to correspond with higher levels of satisfaction.
Children growing up in Britain are also more likely to experience sibling bullying than their peers in the United States, Israel and Italy, the study found, with 54 percent of all siblings in Britain saying their brothers and sisters bullied them.
The survey also found one in six households was in poverty, with pensioners and families with children most likely to fall into this category.
"The findings will inform not only individual life choices but also government policy, directing efforts towards those who need it most, David Willetts, Minister for Universities and Science, said in a statement.
The findings come less than a week after Britain started measuring national happiness to see how satisfied people living in Britain are with their lives.