the partner bit is very true . mine loved me and hated women. (greys/parrots quite often take a shine to one particular gender).
when my youngest daugter was badly bitten i had to let 'ernie' go to a good home.
greys are a massive commitment ,they need a lot of TLC and can live as long as humans.
mine was hand reared but by the sounds of it yours isnt.treats are the key to taming down.once you find out his favorte treat he/she will soon step up onto your hand............try grapes !