Sex therapists help patients resolve sexual difficulties and experience healthier, fully-expressed sexuality with themselves and with others. In order to be effective, sex therapy must be evidence-based, aiming to treat the symptoms presented by the client. However, as sexuality is expansive and complicated (both for the clients as well as the sex therapists), this (evidence-based) therapy cannot be done without taking into account the psychodynamic view in general, and the transferencecountertransference processes accompanying each therapeutic dyad (or sometimes, triad) in particular. After an introduction of sex therapy and of the PLISSIT model (Anon, 1976), I use a case study in order to demonstrate how awareness of transference-countertransference processes help overcome therapeutic bypasses in the therapy. I suggest an improved, integrative, PLISSIT conceptualization and possible implication of the use of dynamic understanding as part of evidence-based sex therapy.