Maintaining a satisfying marriage and high levels of well-being throughout adulthood is important but difficult. This research used a longitudinal study of women to investigate how contextual factors impact change in marital satisfaction over time and what factors affect the normatively strong link between marital satisfaction and well-being. I found that marital satisfaction increased over middle age as children left home because individuals began to enjoy time with their partners more. And marital investment (i.e., investing time, energy, and interest in one's marriage) was associated with higher marital satisfaction as well as a stronger link between marital satisfaction and well-being. Taken together, these findings suggest that it is possible to maintain a satisfying marriage over time given a partner with whom one enjoys spending time augmented by the investment of time and effort in the marriage. But marital investment does have a down side. Individuals highly invested in unsatisfying marriages experienced lower levels of well-being and higher levels of depression than less-highly-invested individuals.