According to https://en.wikipedia.org/wiki/Esperanto_etymology
edzo appears to be a back-formation of edzino (wife). Zamenhof said the latter derives from kronprincedzino (crown princess), borrowed from the German Kronprinzessin, and then internally analyzed as kron- (crown) princ- (prince) edzino (wife). However, Vilborg's Etimologia Vortaro argues that edzino is more likely to have come from Yiddish רביצין rebbetzin (rabbi's wife, Mrs.), reanalysed as rebb-etzin, and that Zamenhof made up the German etymology after the fact to avoid anti-Semitic prejudice against Esperanto. That would mean that edz- ultimately derives from the Slavic feminine suffix -its(a). Regardless, few words have histories this convoluted.