This paper suggests a broader definition of perversion as an ego defect that interferes with the adequate resolution of object choice. It relates this defect in part to problems of dysregulation that may arise in the dyad and continue as a cumulative trauma throughout childhood, leading to distortions of pleasure-pain regulation and object constancy. Beating fantasies in two cases are explored to show how the perverse dyad precludes separation and autonomy, excludes the oedipal third and repeats in the treatment as an unpleasurable sadomasochistic transference.