This study describes the family conflict related to the infidelity of a husband through the perspective of
family therapy. The purpose of the study was to find the factors that affected infidelity and family
conflict. This study also attempted to discover factors that influenced positive changes in family
relationship. The data consisted of recorded transcripts and notes taken during 21 family therapy sessions,
which included individual, couple, and family counseling sessions. This study used the matrix and network
display developed by Miles and Huberman as well as the open coding method to show the results of the
study. The therapist employed the MRI’s interactional model and Murray Bowen’s family systems theory in
order to treat the family. The results of the study identified infidelity, undifferentiation of self, and
dysfunctional communication pattern as factors affecting family conflict. As a result of intervention, the
family members experienced the differentiation of self and changed pattern of communication. Through
these experiences, the family members improved their relationship. This case study suggested that both
MRI model and Murray Bowen’s family systems theory were appropriate models for a Korean couples’
infidelity case.