The effects of infidelity on the sexual relationship of the couple are often a neglected part of affair recovery. Therapists may minimize the need to do a thorough assessment of the sexual relationship, or perhaps feel at a loss about how to intervene. This article presents four common clinical presentations of the possible effects of an affair on the sexual relationship of a couple: (1) a marked decrease in sexual activity/complete abstinence, (2) a marked increase in frequency, (3) the development of sexual dysfunction, or (4) shifts in sexual behavior and/or expression. Case studies highlight the ways in which an affair can have an immediate and/or ongoing impact on the sexual relationship of the couple. Assessment and brief intervention suggestions are included that clinicians can incorporate into their existing affair recovery protocols.