Dog behavior?

you could take your dog out running or hiking with just you and your dog, bonding. or have some kind of activity which will reassure her that her role in your family is just as important now, as it was before you got married. dont believe that just coz your wife spoils your dog, that your dog has transferred her loyalty. this is not possible, you got her at three months, and you were her first master. a breeder friend of mine explained this to me when he asked me to hurry and pick a dog of my choice from a litter of malamutes. he then asked me to pick it up and bring it home at 2 1/2 months old, too early a time to separate the dog from his mom, but as the breeder explained through his observations (he has been a malamute breeder for a long time), it's important that your dog bonds with you right after he is separated form his mother, this will enable you to have a smoother time with teaching your dog commands, i suppose it is like saying you have to be his first alpha, which you are to you dog. so i hope that some hours of bonding time alone with your dog will solve your concerns.

When a dogs behavior radically changes, it is usually due to a medical problem rather than a loss of "leadership".

That old "dominance theory" was debunked many years ago by professional trainers, so that doesn't enter in to your problem.

Dogs pick favorites, and many times it has nothing to do with who feeds, plays, or trains them.

I suggest a good medical exam, including a thyroid panel (very often the answer to a major change, especially at the age your dog is). If all checks out clear, go back to reviewing the earlier training you gave the dog and have your wife work with you.

You have to show dominance over her, just a mentality where she HAS to do everything once you command it or else she gets no treat, again start with treats like you would training a puppy. Keeping a dog well trained takes consistency and regular training. It doesn't have to be much but you could simply practice an exercise a couple times a week to keep her brain active as she is probably a little rusty

You don't have to be pack leader, dogs don't have pack leaders, but you have to keep training her as you did before. Just repeat regularly some obedience training and she will realize that if she wants something she has to work for it. Also teach your wife to give treats only in response to the dog doing something for her, even if it is something as simple as sit.

if you don't spend enough time with her she will stop obeying you. If you want her to listen you have to practice with her every day basic commands and go for walks and have some fun time playing