In an article newly published in the journal Social and Personality Psychology Compass we use the context of the COVID-19 pandemic to test a classic theory about how different levels of stress impact relationships. Tesser and Beach originally raised the possibility that moderate levels of stress are the most harmful for relationships in a 1998 study in which they found that the association between stress and individual well-being was linear, whereas the association with relational well-being was non-linear. The current study sought to conceptually replicate this study within the context of the COVID-19 pandemic by examining associations between stress and individual versus relational well-being, using a sample of 654 individuals who were in a committed relationship in the early weeks of the pandemic. Results were somewhat consistent with those of the original study: the association between stress and depression was linear, but the association between stress and relationship satisfaction was non-linear. However, the form of the association between stress and relationship satisfaction was different than observed in the original study. These results point toward the need to better understand how the severity of a stressor impacts relational outcomes, including the characteristics of stress that lead to stress spillover and the circumstances under which relational outcomes are resilient to high levels of stress.