From the abstract:
Are the marriages of lower income couples less satisfying than the marriages of more affluent couples? To address this question, we compared trajectories of marital satisfaction among couples with a wide range of household incomes. The marital satisfaction of 862 Black, White, and Latino newlywed spouses (N = 431 couples) was assessed five times, each 9 months apart, during the first 4 years of marriage. Lower income couples did not have less satisfying marriages on average, nor did their satisfaction decline more steeply on average. They did, however, experience (a) significantly greater fluctuations in marital satisfaction across assessments and (b) significantly more variability between husbands and wives. If efforts to support the marriages of low-income couples are to address the unique characteristics of their marital development, these findings suggest that efforts to stabilize their marriages may be more effective than efforts to improve their satisfaction alone.One of the key findings from Charles Murray's Coming Apart was that stable marriages are a feature of the top quintile whereas divorce is a greater feature in the bottom quintile.
The research implication (if it is true) is that the issue is not so much with the quality of the marriage but with the stability. An important insight. As money is one of the most common sources of stress within a marriage, I wonder if that is not the driver here. If it is, then, perhaps, one of the best mechanisms of increasing marital stability among the poorest, is not training in marital communication, but rather in training around financial planning and management. If you reduce the financial variability, you reduce the marital variability and therefore increase marital sustainability. Maybe.