Simpler and cheaper weddings could encourage more people to marry, a think tank has said.
Research by the Marriage Foundation found that the marriage gap between rich and poor has doubled in the last 30 years, with the proportion of parents to newborn babies falling from over two thirds (68%) in 1988 to a third (35%) in 2019.
While there has also been a fall in higher income groups, it is less stark (91% in 1988 vs 76% in 2019).
Commenting on the figures, the Marriage Foundation said the perception that weddings are expensive could be a deterrent to more people tying the knot.
In a 2012 survey by law firm Seddons, cost was the biggest reason why over half of men (51%) and a third of women (38%) either cohabiting or in a relationship said they had not married.
In 2018, a survey by wedding planner app Bridebook found that the average cost of a wedding in the UK had reached £30,355.
Marriage Foundation founder, Sir Paul Coleridge, said that glossy magazines and "far-fetched" social media posts had created "unrealistic expectations" about the big day.
"For too many, the idea of marrying has meant primarily a huge and overly expensive reception which misses the real point of the marriage," he said.
"So, our message is clear, keep it simple and never let the cost of a wedding be a barrier to marriage.
"If family breakdown is to be tackled effectively the place where policies should be concentrated, is on the reduction in the rate of marriage. And the place to start is with the pernicious perception that marriage is out of date and only for the rich."
Marriage Foundation researcher Harry Benson said it was important to reinforce the message that a couple "does not need to spend a fortune on a lavish Hello-style wedding".