Greys do tend to pick one human partner to bond with, unfortunately there isn't much you can do to change their minds.Your grey obviously feels your partner is that person,that doesn't mean that you cant have a relationship with her, continue being the one to give treats etc..hopefully in time she will associate you with good things.Three days isnt long at all,she needs to adjust to her new environment & new human family.
Many people believe a male grey will bond with a female human & vica versa,i personally don't agree with that,i have both sexes that are bonded with me,i do believe its down to the personality of the individual grey.