Doubling up, or living in another person’s household, has been rising since the Great Recession. This paper looks at a particular case of doubling up: married and cohabiting couples who live in another household. We examine the prevalence of these subfamilies, focusing on differences between younger and older couples, using the 2007–2014 Current Population Survey. Decomposition analysis reveals that being out of the labor force explains about 67% of the rise in subfamilies since the recession. For younger couples economic insecurity plays a bigger role in the likelihood of living in a subfamily, whereas for older couples health and caregiving are more important. Nonetheless, neither socio-economic characteristics nor local housing and job markets could entirely explain the positive effect that the recession had on the likelihood of living in a subfamily. We conclude that the recession changed household composition, as more couples doubled up and became subfamilies, but that this change is outlasting the recession. The Great Recession has left an enduring footprint on the living arrangements of married and cohabiting couples.