If you discontinue positive, individual interactions with your birds, there is definitely a possibility of one bird preferring their now perceived mate/best feathered friend over you. Flock interactions in the wild determine and build relationships, and in our homes it's no different. My IRN is the same as your AG. He'll regurgitate and display non-stop for Avery, my GCC. I often interrupt it because:
a.) Avery doesn't like it and is very much so bonded to me, and
b.) I also fear that he will bond too strongly to her and her alone (though ring necks are known for their promiscuity and frequent changing of favourites).
Do you have scheduled interactions with each bird individually, where you train/engage/entertain the bird with one-on-one time? If not, I would work towards that. Just like people-to-people friendships take dedication and time spent, our relationships with our fids require dedication and trust building interactions to maintain a healthy and happy relationship.
Alternatively, you could try and discourage the regurgitating, though you make receive a nice chomp if your AG is determined in sharing his love-goop...
