Data on the incidence of mental illness as related to sex and marital status, as well as studies on role differences between marital partners tend to support our conclusion that wives are more likely than husbands to show a negative effect on their mental stability when one partner of a marital pair is a psychiatric patient. A model about the relationship between mental stability, role-enactment and marital satisfaction is proposed. It is assumed that the effects of this relationship differ according to the sex of the identified patient. On this basis, a different therapeutic approach is recommended for the conjoint treatment of marital pairs according to which partner is the identified patient.