Taking into account the secretive nature of infidelity experiences and their adverse impact on the involved partners, the aim of the present qualitative study was to examine how individuals—who have been engaged in extradyadic relationships, as “affair partners”—narrate their experiences in an online support group. The study analyzed 60 posts, published over a period of 6 months in an online support community. Three main themes emerged through the thematic analysis conducted. The first theme involved conflicting dimensions of affair partner experience, in which the following sub-themes were identified: 1) living in the shadow of loss, and 2) the prevalence of ambivalence: when opposite impulses coexist. The second theme refers to the centripetal aspects of the relationship and within this section the following sub-themes are defined: 1) the relationship as a supportive environment and 2) between plenitude and dearth: the desire for exclusivity. Finally, the third theme refers to the lessons learned by the affair partners and their generalizing conclusions such experiences. The present study underlines how group participants reconstruct their experiences of extradyadic relationships and how they create new ways of meaning making about them. The findings involve reflexive conclusions about intimate relationships capturing elements of broader cultural narratives, representations and dilemmas of self and relationships, as presented in written transactions in online support groups.