The idea of a "trophy" wife or husband may not sound like a very romantic basis for marriage. It implies one half of a couple brings physical attractiveness to a relationship, while the other half brings status and money.
Author
- Joanna Syrda
Assistant Professor in Business Economics, University of Bath
But the lack of romance in this idea does not mean that attractiveness and wealth don't both play a part in many real relationships . Sociologists call it "beauty-status exchange", and it has traditionally reflected the gendered idea that men prioritise physical attractiveness in the search for a spouse, while women opt for wealth or earning potential.
While it might seem like an old-fashioned concept, my research suggests that, after marriage, some heterosexual couples still try to find a balance between money and attractiveness - but now it may be common for this to affect both sexes in more similar ways.
I found that increases in one spouse's share of household income were strongly linked to reductions in the other spouse's body mass index (BMI). It appeared that when the share of household income earned by the wives in my sample rose, their husbands tended to exercise more and slim down.
And when the husbands' income share rose, their wives tended to respond in a similar way. So the beauty-status exchange lives on - only now it appears to be more equal.
My research used 20 years of US data about more than 3,700 dual-earning heterosexual couples, comparing the share of total household income with changes in both partners' BMI and how often they exercised.
What was once widely thought of as a gendered, one-sided exchange, may have become a mutual process of balance, maintained in part through deliberate changes in fitness routines. These effects are largely symmetrical, holding true for both men and women.
BMI is, of course, an imperfect measure of physical attractiveness. It has many limitations and captures only one dimension of a person's appearance and fitness.
But it is one of the few measurements consistently available for both partners in large and detailed data sets. It has also been linked with perceptions of attractiveness in previous research , which makes it widely used in studies about couples and relationship dynamics.
Equilibrium
Economists and psychologists have long described relationships as systems that strive for equilibrium . Each partner can compare what they give and receive and adjust when things feel out of balance.
Building on this idea, my study introduces the concepts of "static" and "dynamic" beauty-status exchange.
The static version refers to the one-off trade between attractiveness and status that shapes who marries whom. This is a pattern documented in previous research showing that higher-earning men are, on average, more likely to partner with women with lower BMI - a proxy for "socially defined physical attractiveness".
The dynamic version captures how this exchange continues within marriage, as couples adjust to shifts in income and resources to maintain balance over time.
Relationships, in other words, evolve. As incomes rise or fall, people respond not just financially but physically, subtly reshaping themselves to preserve what feels like fairness or desirability within the relationship
This search for balance aligns with the fact that in some of the world's wealthiest countries - including the US , the UK and parts of Europe - the share of households in which wives earn as much as or more than their husbands has increased.
As this financial equality grows, so too does cultural equality in expectations about appearance. The rise of male grooming markets and the normalisation of skincare and body image conversations among men all signal a shift: men now invest far more in how they look than previous generations did.
Dynamic beauty-status exchange captures this broader trend at home. Economic parity between partners is matched by a new form of aesthetic parity, where both men and women feel motivated to maintain attractiveness in response to changes in status or income.
What was once a one-way cultural expectation appears to have quietly become a two-way performance of equality. The beauty-status exchange hasn't disappeared; it has simply evolved.
Where once men's income and women's appearance were traded asymmetrically, today's dual-earner couples may engage in a more reciprocal form of exchange. Beauty-status exchange is, of course, only one of many ways couples adjust to maintain balance, alongside emotional support, housework and childcare for example.
But it offers a clear window into how economic change can reshape behaviour within marriage.
Overall, shifts in income share are mirrored by shifts in behaviour and body weight. Marriage, it turns out, remains a dynamic marketplace of mutual adjustment.
Joanna Syrda does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
