Men from poor backgrounds are around twice as likely to be single than those from rich families by the time they reach early middle age, analysis has found.
As well as being more likely to be in highly-paid jobs or even working at all, richer men in their early 40s in Britain are also more likely to be living with a partner, according to the findings from the Institute for Fiscal Studies (IFS).
It found the likelihood of being in a relationship, and a partner's level of earnings, are increasingly related to family background.
In 2012, around one in three (33%) men aged 42 from the poorest fifth of households lived alone, the research found. This compared with one in seven (15%) of their counterparts from rich backgrounds living without a partner.
Men from low income households were more than twice as likely to be divorced as those from high-income backgrounds, at 11% versus 5% and nearly twice as likely never to have been married, at 36% versus 20%.
Richer men were also more likely to have higher-earning partners. The partners of men from richer backgrounds tended to earn around 73% more than the partners of men from poorer families, the research found.
As women's earnings are an increasingly important part of a household's income, these trends significantly reduce the household incomes of men who grew up in poor families compared with those of men who grew up in rich families, the IFS said.
The report suggested this is quite a "new divide". Among men born 12 years earlier, the differences in partnership status and partner earnings by family background were considerably smaller, the IFS said.
The earnings gap between men with richer parents and their counterparts from less well off backgrounds was also found to be widening.
In 2012, employed 42-year-old men whose parents were among the richest fifth of households earned on average 88% more than those from the poorest families. In 2000, the gap was 47%.
Men from poorer backgrounds were twice as likely to be out of work as those from richer backgrounds.
Only 7% of men growing up in the richest fifth of households were out of work at the age of 42 in 2012, while more than 15% of men from the poorest fifth of households were out of work.
The research explored the importance of family background for household income using several sources, and was produced with funding from Closer, (Cohort and Longitudinal Studies Enhancement Resources).
Chris Belfield, a research economist at the IFS and an author of the paper, said: "Focusing solely on the earnings of men in work understates the importance of family background in determining living standards.
"As well as having higher earnings, those from richer families are more likely to be in work, more likely to have a partner and more likely to have a higher-earning partner than those from less well-off backgrounds.
"And all these inequalities have been widening over time."
Alison Park, director of Closer, said of the research: "It shows how existing differences in the earnings of men from richer and poorer backgrounds are exacerbated by a new divide, with poorer men in their early 40s being less likely than those from wealthier backgrounds to be living with a partner."