German Shepherd re-bonding

Question
My wife and I have a female white GSD, 6 months old, about to be spayed this Friday. When the dog was about 2 months old she bonded with my 18 yr old son when he was over and playing with her a lot. My wife wanted the dog to bond with her, but ever since that time with my son, when he comes over every 2 weeks, the dog treats him as though he is all that matters.  My son will be going to college soon, but we will still see him some; how can my wife become the permanent main bond in the family to our dog? When my son isn't around, my wife seems like the main bond, but what can we do (and not do) to so that my wife is always the main bond?

Answer
I am not sure she will ever forget your son.  I raised a German Shepherd for a dog guide school a few years ago.  They retained her as breeding stock and placed her in a home nearer the school.  The people had her mother and love her deeply.  Still, she is very excited the occasional visit I have with her.  

Your dog is too big for some of this, but it will help the bonding with your wife.  

''Elevation for small puppies: Sit on the floor and gently put your hands around your pup's middle, below his front legs, and lift him up. He is facing you. Hold him for 15 seconds. Repeat until he no longer struggles. If he is past 10-12 weeks, lift his front feet off the ground, but don't pick him up.

Cradling for small puppies: Hold your puppy gently on his back, as you would cradle a small baby. If he struggles, hold him firmly until he quiets for 10-15 seconds. With larger pups, you can do this as your sit on the floor, with your pup between your legs.

Quiet lying down: Place your pup on the floor on his side, with all 4 legs pointing away from you. Use your hands on his neck/shoulder area and middle, to hold him in this position. When he is quiet, praise him. Lengthen the time that you keep him quietly in this position. When he accepts this position well, handle his paws and muzzle, while keeping him quiet.''

The quotes mean this isn't my original work. It is copied from my Puppy Raising Manual. I have long used these or minor variations of them, and they are very effective. You may want to give him a belly rub while he is on his back too. Helps bonding. There is a big difference between him rolling over and demanding a belly rub, and you choosing a time to roll him over and rub his belly. The latter cements your place as pack leader.