Conventional wisdom, psychological theory, and indirect evidence suggests partnered sexual activity has stress-relieving properties. The present research thus aimed to provide a well-powered test of the association between sexual activity with one’s partner on a given day and changes in stress. We further aimed to explore whether any association between partnered sexual activity and changes in stress depends on (1) biological sex, (2) marital quality, (3) the quality of the sexual activity or (4) the motives underlying the sexual activity. In pursuit of these goals, we pooled three independent, dyadic, daily-diary studies of newlywed couples (N = 645 individuals; 319 couples) to examine the daily association between dyadic sexual activity and changes in stress. Although dyadic sexual activity on a given day was associated with reductions in stress that same day, it was not associated with any further reductions in stress the next day [italics supplied]. Neither of these associations robustly depended on biological sex, global marital satisfaction, satisfaction with sexual activity when it occurred, nor engaging in partnered sexual activity to approach positive experiences with one’s partner. That said, engaging in sexual activity to avoid negative experiences with one’s partner was associated with increases in stress the following day. These findings (1) enhance our understanding of the temporal boundary conditions under which sexual activity may have stress-relieving properties and (2) suggest that simply examining occurrences of partnered sexual activity without considering people’s motives underlying their decision to engage in such sexual activity may ultimately obscure its ability to relieve (or exacerbate) stress. [bold lettering supplied]