Understanding ways to improve the public health impact of public-facing, evidence-based mobile apps is critical. This study will test a low-cost, "high-touch" approach to improving the outcomes associated with use of the PTSD Coach and PTSD Family Coach mobile apps,which are already available to the general public and used by over 55,000 new users per year.This study will test whether the involvement of an intimate partner in the use of a mobile app for PTSD will result in changes in how the mobile apps are used and in relationship quality and PTSD symptoms over time. Additionally, this study will test whether the addition of a discussion board can improve engagement with the apps and/or outcomes. The study will also provide useful qualitative data that can inform the development of subsequent dyadic interventions using mobile technologies.