Do couples last longer when they live alike? Across studies covering millions of couples, partners resemble each other on most traits researchers have measured, from education to political views. The differences that remain, such as how much each person drinks or how each one handles money, are the ones that longitudinal studies tie to divorce.
Plans for Children
A decision about children allows little compromise, and more adults are choosing not to have them. In a Pew Research Center survey, the share of Americans under 50 without children who said they were unlikely ever to have kids rose from 37% in 2018 to 47% in 2023. Among those adults, 57% said a major reason was that they did not want children, and younger adults were more likely to say they wanted to focus on other things, such as a career or personal interests. Concerns about the state of the world were another reason younger adults cited.
For two people dating in their 20s or 30s, this is a question to settle early. One partner’s yes and the other’s no leave no middle option.
Sleep Timing
Partners who keep different hours can still do well, although the research points to some costs. A study of 91 heterosexual couples found that similarity in chronotype, meaning a person’s natural preference for mornings or evenings, was linked to higher relationship satisfaction among women but not among men, and women who were morning types also reported higher satisfaction. Sexual satisfaction for both partners was higher when their preferred times for sex were closer together.
A smaller study of 32 couples found that pairs with matched chronotypes reported better sleep quality and greater sexual satisfaction than mismatched pairs. The effect appears to fade with time. Chronotype similarity was tied to satisfaction in couples together for about 4 years, and it made no measurable difference in couples together for about 25 years.
Age and Life Stage
An age gap changes which lifestyle questions come up first. When you are dating someone older than you, the compatibility questions include life stage, such as one partner planning for retirement while the other is still building a career or deciding about children.
In a 2008 study published in Psychology of Women Quarterly, psychologists Justin Lehmiller and Christopher Agnew tested evolutionary and socio-cultural predictions about heterosexual women in age-gap and similar-age relationships. They found that women with older partners were the most satisfied with and committed to their relationships, compared with women whose partners were younger or close to their own age. The authors described the result as consistent with socio-cultural explanations of partner choice. They also found that satisfaction, investments and beliefs about social norms explained commitment differently in age-gap couples than in similar-age couples.
Money Conflict
Arguments about money predict divorce more reliably than arguments about anything else. In a 2012 study, Jeffrey Dew and colleagues at Kansas State University used national survey data on 4,574 couples to compare types of marital disagreement. As later coverage in Fortune summarized, financial disagreements between spouses were the strongest disagreement type to predict divorce, for wives and husbands alike.
For men, money was the only type of argument that predicted divorce. Once the researchers accounted for money arguments, a couple’s actual financial situation was not associated with divorce, and arguments about money tended to be longer and more intense than other disagreements.
Drinking Habits
A Norwegian study followed 19,977 married couples for 15 years and published its results in Alcoholism: Clinical and Experimental Research. The researchers found that heavy drinking raises the risk of divorce, and that the risk climbs as consumption rises. It was highest when the wife drank heavily and the husband did not, a pairing with about three times the divorce risk of couples in which both drank moderately.
Matched habits lowered the risk. Couples who drank similar amounts had a lower risk than their individual drinking levels would suggest, and the researchers advised couples to talk about drinking before marriage. Over the 15 years, 17.2% of the heavier-drinking couples divorced, compared with 5.8% of light-drinking couples.
The researchers offered two explanations for the stronger effect of a wife’s heavy drinking. Heavy drinking is less socially accepted for women, and husbands may be more likely to leave a marriage in response to it.
Household Chores and Shared Priorities
In a Pew survey of more than 35,000 married adults conducted in 2014 and 2015, 56% said sharing household chores was very important to a good marriage. The only elements rated higher were shared interests, at 64%, and a satisfying sexual relationship, at 61%.
As reported by MinnPost, sharing household chores outranked shared religious beliefs at 47%, having children at 43% and adequate income at 42%, while agreement on politics was named by 16%. Younger married adults gave chores more weight. Among adults 18 to 29, 67% called chore-sharing very important, compared with 56% of those 65 and older. The Pew researchers noted that the survey did not define what sharing meant, and that differences in hours worked, even when both partners work full time, can shape how chores are divided.
Similarity Across Traits
A 2023 analysis led by Tanya Horwitz combined about 200 published studies of millions of couples with data from the UK Biobank. For 82% to 89% of the traits studied, partners were more alike than different, and only about 3% of traits showed partners pairing with people unlike themselves. The researchers found no compelling evidence that opposites attract on any trait. UPI’s coverage of the study listed the strongest matches as political and religious beliefs, education, some measures of intelligence, and smoking and drinking habits.
Personality traits showed weaker links, although partners were still more alike than not. Chronotype was one of the few exceptions, with night owls pairing somewhat more often with early risers. Horwitz noted that the study looked at cohabiting and co-parenting couples, so the findings describe long-term relationships. UPI traced the old saying that opposites attract to psychology from the 1950s.
Partner Correlations for Politics and Temperament
In the partner-similarity data, compatibility is mostly a matter of shared views and habits. Political values correlated at .58 between partners, while neuroticism correlated at only .11. Two people with the same politics and drinking habits are the typical couple in this research, and two people with matching temperaments are much less typical.
