“Splitting”, as stressed in the Object Relations Theory, is a very important psychological state in human development. It refers to a sense of contradiction and conflict of “being split into all good or all bad” formed since birth through perceptions of significant others and surrounding environments, which are sometimes good and sometimes bad. When a baby does not have sufficient knowledge to understand why significant others are sometimes upset and sometimes happy, he/she would instinctively exclude some feelings and characteristics （usually bad ones） in order to protect himself/herself from external disturbances. This process of excluding some parts of feelings and characteristics is called “splitting” in the Object Relations Theory. We found from clinical experience in marriage counseling that the psychological state of “splitting” and whether the split parts can be integrated back to the self are quite important for healthy marital relationships. Couples who repeatedly have affairs are often deeply affected by the state of “splitting”. This study is aimed to examine how “splitting” works in an affair and how integration of internal splitting was carried out by unfaithful husbands through their marriages. Data was collected by conducting five in-depth interviews with a man who had been unfaithful to his wife. Based on the Hermeneutic Phenomenology approach, data analysis was further performed through discussions and dialogues between the interviewee’s narratives and the theoretical texts with regard to “splitting” in the Object Relations Theory. This study found that the “split” affections of unfaithful husbands consist of four layers: （a） experiencing the state of “splitting” between the good and the bad of external object in adulthood intimate relationships; （b） experiencing the good and the bad of self in the extramarital affairs; （c） experiencing the mutual exclusion and conflicts between the id and the superego during the affairs; and （d） becoming aware, while struggling with the affairs, of the unresolved “split” affections from the family of origin. In the integration of “split” affections, there are also four corresponding processes: （a） integrating the good and bad affections through the “good-enough” sexual experiences; （b） experiencing the integration of good and bad on the proposed, constant object; （c） accepting the maternal and super-ego images projected onto the partner; and （d） becoming aware of the unresolved issues from the family of origin that are carried over to the current marital relationship. It is believed that an affair can be considered as “acting out” the internal “split” affections. When rebuilding a marriage after an affair, we must work on not only healing the pain and loss of the betrayed but also help the unfaithful partner to understand where this undermining impulse came from. In addition, the “reconstruction of sexual relationships” might be an essential factor in counseling marriages involving affairs, for it enables the unresolved issues formed in the families of origin to emerge onto the consciousness where they can be worked on by the couple.