The impetus for this study is the proposition that social network sites (SNSs), like Facebook, can be beneficial for romantic relationships via network support functions. This study investigated a model which proposes that the use of Facebook predicts relationship support from Facebook connections, and this, in turn, predicts relationship stability and satisfaction in romantic relationships. This mediation model was tested on data gathered via an online survey among individuals who use Facebook, who are in long-distance (LDRR, n = 142) and geographically-close romantic relationships (GCRR, n = 314). GCRR participants reported higher levels of Facebook intensity and relationship support, as well as perceived relationship stability and satisfaction than participants in LDRR. Moreover, the results indicated that Facebook intensity predicted higher access to Facebook relationship support in LDRR and GCRR which, in turn, predicted perceived relationship stability and satisfaction in LDRR; and only perceived relationship satisfaction in GCRR. However, Facebook intensity had direct negative impacts on relationship satisfaction in GCRR, and on perceived relationship stability in LDRR. Facebook intensity and Facebook relationship support were not associated with relationship stability in GCRR. This demonstrates the relative importance of SNSs, such as Facebook, in relationship stability for those in LDRR.