Late response but i just joined up.
My husband (Neil) and i had the same problem. We got our African Grey at 3 months old and he bonded to both of us (he's 8 now). We owned a business and Pickles would go to work with us and stay behind the counter where we kept a cage and play stand. One day, a repeat customer came in and thought it would be okay to go behind the counter and have Pickles step up. It happened so fast that i didn't have time to react and stop it. Pickles started to run up his arm but the guy stopped him by grabbing his beak and shaking Pickles head. He did this gently but Pickles did not like this at all. I got Pickles off the guy right away but from that moment on, he stopped liking men - including Neil. He would talk and interact but if men came close, he bit.
This went on for several months and it wasn't a big deal at that time because Neil was working out of town most of the time but once he returned, he wanted to be part of Pickles life again. I came up with a plan ...
I backed off and Neil became Pickles primary caregiver. I continued to feed him and clean the cage but Neil did all the fun things with him - snacks, talking, taking him for walks around the house, playing with him on the couch etc. All interaction between Neil and Pickles was fun and only fun.
Pickles learned quite fast that if he wanted snacks or to do anything entertaining, it would only be with Neil. Within a few weeks they had bonded better than in the beginning. Now Pickles preferred him to me but every time the pendulum swung, the other person would back off a bit until Pickles came to like us equally.
You have to be consistent. Your husband needs to back off for awhile, and that's hard because of course he wants to interact with him. However, it's not fair to you - and he should understand that and be willing to help.
Take it from me - there is no such thing as a 'One Person Bird'. It just takes time and patience. My husband actually wrote an article for Good Bird Magazine (
www.goodbirdinc.com) a few years ago, entitled "The Myth of The One Person Bird". In the article he states that it's not only unfair for the other person to accept the idea of a one-person-bird, but also that it's not fair to the bird. If a bird lives it's life as a one-person-bird, it will be a difficult life for him once his preferred person is gone.
By the way, he likes all men now too - not just Neil.
I hope this helps - we've helped several people with this simple plan. Good luck!