Marriage rates have fallen dramatically in most major European countries over the past decade, as austerity, generational crisis and apathy towards the institution deter record numbers of young people from tying the knot.

The number of weddings has fallen to historical lows in France and Spain and has tumbled in other Catholic countries such as Italy, Ireland, Poland and Portugal, according to national and European data. But people have also fallen out of love with marriage in countries as varied as Greece, Denmark, Hungary, the Netherlands and Britain. Only in parts of Scandinavia, the Baltic republics and Germany is the institution retaining its allure.

In Italy there were fewer than 200,000 marriages last year, the lowest number since the first world war. Numbers have fallen by 24% in the past decade and halved since 1965. Preliminary data indicated that the rate of marriages in Italy last year was 3.3 per 1,000 citizens, said Istat (Italy's National Institute of Statistics), compared with 4.6 in 2003. It was, it said, "the lowest in modern history".

"The fall has been very significant and beyond all expectation," said the institute's chairman, Antonio Golini. "There are cultural and economic causes for this phenomenon," he said. "The cultural causes are that marriage has become less important from a religious and civil point of view, because many young people live together without marrying.

"But there are also economic causes because marriage means having a celebration and often this celebration is big and costs a lot. So in a time of crisis like this, people live together in an [unmarried] cohabitation."

Economic crisis not only means people wanting to save money on a party. A study this year found that almost half of people aged 18-30 in Europe still live with their parents, prevented from flying the nest by a lack of jobs, large debts and rising property costs. Experts say this perfect storm of factors is also hitting birth rates.

"The lack of stable jobs and absence of credit have become disincentives to forming a family," said Teresa Castro-Martin, professor of research in the department of population studies at the CSIC, a government research institute in Spain. The average age of newlyweds in Spain is now 37.2 years for men – almost 10 years higher than it was in the 1980s. "Marriage has traditionally been a rite of passage to adulthood but it has lost its centrality," said Castro-Martin.

In France the downward trend in marriages has been partly affected by the rise of civil partnership contracts. In 2013 for every three marriages there were two civil partnerships, known as PACS (pacte civil de solidarité), which were introduced in 1999.

Magali Mazuy, a demographer at the French National Institute of Demographic Studies, said the dip in the number of marriages could in part be attributed to the popularity of the PACS, but also noted that "only a fraction of pacsés [people with PACS] subsequently get married". She saw marriage as "a hard core of people attached to traditional values, or who choose it for what it symbolises: the notion of couplehood, commitment and faithfulness." But she also said that marriage was seen as "protecting" the spouse or children in case of death, whereas the PACS provided less protection.

Declining marriage rates in Greece – though exacerbated by the country's debt crisis – have been a fact of life for the past decade, sociologists say. Changing lifestyles and behavioural patterns as much as economic pressures have been at the root of the fall. More than 60% of Greek youth are unemployed – the highest in the EU.

"The tendency started way before the crisis struck and is as much about changing values as the financial difficulties that young people now face," said Aliki Mouriki, at the National Centre for Social Research. "As so many have difficult access to a decently paid job without long hours of unpaid overtime, they're not keen to commit themselves to the obligations of wedlock and do so, if and when, pregnancy occurs."

The realisation that they won't be able to provide – combined with a reluctance to give up what Mouriki calls "their bohemian, uncommitted way of life" – has meant that many young Greeks are simply postponing exchanging vows.

The decline is not limited to "old Europe". Last year the number of weddings in Poland fell to its lowest since 1945 – the flip side of a society in which 43% of 25-34-year-olds still live with their parents. Witold Wrzesien, a sociologist, said young Poles today wanted "independence without responsibility. They want to be treated with the respect accorded to adults while staying under the safety of their parents' wings and not taking any risks. "

"In short, they want to eat their cake and have it."

However, the reasons for the drop in Polish marriages are not just economic. The number of children now born out of wedlock in Poland is at its highest level of 21%, suggesting significant shifts in social attitudes in a country which is 95% Roman Catholic and has up until now been considered one of Europe's most traditional societies.

Wedding refusers

Italy

Germana Chemi, 30, and Carmelo Cardea, 38, from the southern city of Reggio di Calabria, have been together for six years and living together for four. In the Italy of 40 years ago they would probably have been married with a brood of children.

"To a certain extent it's because of economic problems. Never having that economic solidity which enables you to pursue long-term projects, we've slightly been taking each day as it comes," said Chemi, who completed a doctorate in philosophy from the University of Pisa this year and is now back in Reggio di Calabria trying to qualify as a secondary school teacher.

The shop into which Cardea poured his time and energy was forced to close this month due to the harsh economic climate.

Despite the difficulties, the couple have managed to create a life together outside their family homes – which, especially in southern Italy, is not a given. "In the past, in order to leave home, you had to get married. Now that's no longer the case," said Chemi.

And, perhaps chiefly because neither is a practising Catholic, they do not feel particularly bothered about tying the knot. "We don't think about it much. It has never been a life goal," said Chemi. "We have focused on our own things, at the same time as being together, without having to spend a year planning a wedding."

France

Mélanie Henry, a 30-year-old tax adviser, met Pierre-Antoine Gendreau, 31, a maths teacher, 12 years ago and they have a one-year-old child, Gaspard. They live together in the eastern Paris suburb of Le Perreux-sur-Marne.

They have not married because "we never really felt like it", although the couple have "got nothing against marriage as an institution", said Henry.

She said they had seen married couples around them break up. Gendreau said "the real commitment for us was to have children".

Four years ago they signed a PACS (pacte civil de solidarité) contract, or civil partnership. "I know it doesn't sound very romantic but we did it for tax reasons," said Mélanie.Henry. "Pierre was working as a chiropractor and I was earning more at the time, so it made sense to pool our resources rather than be taxed as single people, which was costing us more."

Spain

Xavi Piera, 38, & and Judit Paje, 40, have two-year-old twins. "We are opposed on principle to the establishment and patriarchal values that marriage symbolises," said Paje. They also have seen friends marry young and almost all of them are divorced.

"I'm aware that by not being married, although I'm registered as the children's father, if we separated I would have no rights regarding them," said Piera. "Fathers don't count for anything in this country."

He would have rights if they registered as a pareja de hecho (de facto couple), which confers more or less the same economic and parental rights as marriage, but "we reject the state having any role in our relationship. A lot of our friends feel the same way," he said.

Poland

Szymon Krawczyk, 27, and Alicja Pawlicka, 26, have been a couple for three years. Krawczyk is a sales specialist, while Alicja edits books. They say they are "very much in love".

Both of them still live with their parents, as do 43% of Poles aged 25-34. They cannot afford to get married as they are both on small salaries and are on temporary work contracts, which give them no chance of getting a mortgage.

Pawlicka said if they got married and moved into a rented flat and then one of them was to lose their job, they would look pretty silly going back to knock on their parents' door. "Better to play it safe for now," said Krawczyk.

Greece

Thodoros Karkas and Katerina Kontodimos are typical of Greece's 20-something generation. In an ideal world, where money was no obstacle they might have considered marriage, but hooking up under circumstances of near penury is simply not an option. "We could have thought about it more but it's not in our near future plans," said Karkas of the four-year relationship. And as for children, "the money we earn is not enough even for us," he said. "How on earth could we do that?"

A qualified sound engineer and music technology specialist, the 26-year-old met Kontodimos in 2010 when she was a student of interior architecture. Eighteen months later – at the height of Greece's economic crisis – they moved in together, sharing a flat in central Athens. In that respect they were different to most of their friends who were forced to live with their parents to survive.

"Flat-sharing makes the relationship more serious," said Kontodimos, who turned 21 recently. "Some day I would love to have children. When you have children it must feel like you're being reborn in some way."

But it's been an uphill struggle, eking out a living in part-time jobs, waiting on tables and working in bars.

"Our rent is €250 a month [£200] and, all told, we earn about €800 a month when we need about €1,000 to get by," said Karkas, admitting that they often had to seek help from their families to make ends meet.

"It's hard and it's not what we wanted but we live in hope that the future will give us more opportunities to make our dreams come true."