This study has made an effort to determine the causes and forms of infidelity andrnit.s impact~ on ma rried partne rs.rnTo this efTec t data were coll ected from four unfaithful married persons and theirrnpartners Llsing interview guide a nd prope rly a nalyzed qua litatiyely.rnCO l1 sequen tlv, sexual dissatisfaction, emotional dissati s faction, higher n egativerncommunicat ion patterns. premarital scxu;.li l~xpcricncc . IO 'cr rc li g io s iL level andrnconsidera ble age differences were found to be the major causes of infidelity. Thernstudy also identified sexual a nd a combi.nation of sexual and emotional forms ofrninfidelity . Moreo'Jer, the study showed no definite sex difference regarding therncauses and forms of practicing infidelity. Finally, findings showed manyrnpsYchologicaL social. health and re ligious problems ,1:" majo," con seq uences ofrninfide lity on both partne rs and termination of the ir rela tionships as a ,"esult. ofrninfidelity. Possible preventive and intervention actions are s uggested