Abstract: We conducted a nonrandomized study matching 42 women newly diagnosed with breast cancer (sojourners) with 39 trained breast cancer survivors (navigators) who provided one-on-one peer counseling for 3–6 months. Because little is known about how marital status might impact participants in such an intervention, we tested whether being married/partnered buffered navigators and sojourners from distress at baseline and over time. We examined baseline and slopes over time for change in depression and trauma symptoms, and emotional well-being. We were particularly concerned that being matched with a newly diagnosed breast cancer patient might trigger a re-experiencing of trauma symptoms for the navigator, so we examined a re-experiencing subscale. All participants completed baseline, 3-, 6-, and 12-month assessments. Our hypotheses were tested in separate Analyses of Variance (married versus not) for the 39 sojourners and 34 navigators who provided baseline assessments, and the 29 sojourners and 24 navigators who were matched and provided at least one follow-up. We found no significant baseline associations for navigators or sojourners. Being single/not married was associated with increasing depression symptoms over time in both navigators and sojourners compared with being married/partnered. By 12 months, these increases crossed above the clinical cut-off for significant depression symptoms. Single status did not predict increasing trauma symptoms over time. However, being single/not married predicted a significant increase in navigators’ re-experiencing of trauma symptoms. Over time, married sojourners increased significantly in emotional well-being, whereas single/not married navigators did not differ from married navigators. In addition to providing ongoing training and emotional support to navigators, our findings indicate the importance of providing additional support for women who are not married or partnered.