Merlin just turned 14 months old and for the past several months has been inviting my wife to play by nipping and barking at her. If she's in the middle of something (like working on her laptop) and can't stop to play, he gets more and more insistent and nips harder and harder to get her attention. He never does this to me - only to her.
It doesn't seem to be vicious - as I said, it mostly seems playful, but it's making my poor wife miserable. He goes through this phase once or twice a day. She finally went out and got a muzzle for him and that calms him down if she can catch him - he likes to be chased and it seems to me that we are rewarding him for his bad behavior by giving him what he wants.
We had him neutered a few months back and it didn't slow him down any. My guess is that since she's around him the most (she's a stay at home Mom), that he sees her as kind of a surrogate litter-mate and he just feels like he can play rough with her, but who knows?
It sound to me like you are right. I don't believe that a muzzle is the way to go but it does sound like he is being rewarded for bad behavior. My trainer told me NEVER chase them. That is a game and they do love it. That is what the dog park is for. They can chase each other all day long there. I actually had one trainer tell me that if they are running away from you and you call them and they don't come to act like an idiot (her words) running and yelling in the opposite direction. She said that 9 times out of 10 when they realize that you aren't chasing them they will turn and chase you. Then you can catch them.
Is he crate trained? Instead of giving in when he demands to be played with, maybe she could crate him instead of the muzzle. The only thing I ever use a muzzle for is serious biting/attacks.
Is he getting enough exercise? Maybe before she sits down to the computer, she can take him for a long walk and then maybe throw the ball for him. That way she decides when to play, not him. By the time she sits down to the computer he will be too tired to bother her.
I hope you find some of these suggestions useful.
BTW. he is beautiful. I mean handsome.
It sounds like he does see her as a playmate rather than an authority figure. If she could take just a few minutes when he is behaving that way and work on some basic obedience commands with him, it will calm him down and also establish your wife as someone he has to obey.
One good command we taught was "settle". To go to his bed or a specific spot and lay down and stay there until he is told he can get up.
Sounds like typical behavior for Goldens this age. They want to test you and see how far they can push. We've had two act the very same way, and just as in your situation, only to my wife, not to me. As the others have suggested, a little work on obedience and he'll grow out of it. And I would put the muzzle away. No need for that.