In this essay, sexual acting out is subdivided into four forms in orde
r to better define their separate meanings to the unfaithful spouse, t
he partner, and the therapist: affairs, just-sex, making-do sex, imagi
nary partner sex. The conventional justifications for considering any
sexual acting out a form of psychopathology are presented. These justi
fications are more compelling in some forms of acting out than others.
Love affairs, the major subject of this paper, can also be understood
as an existential choice that arises within a large array of social a
nd psychological situations. The conscious experience of the betrayed
and the betrayer is explored. Guidelines for the therapist's role in d
ealing with individuals and couples involved in these life-changing ex
periences are offered.