Hi @amconcerned and @joyh1567, when I noticed changes in my husband's cognitive abilities in addition to withdrawal from social activities, I documented them and sent them to his PCP. My husband did give me permission to proceed, but I would have done it anyway without his permission.
His PCP gave him the Montreal Cognitive Assessment Test for Dementia and told me that my letter was helpful. He then referred my husband to a neurologist. He had an MRI and Neuropsychological testing later. The diagnosis was Alzheimer's Disease.
Maybe you can talk to your wife about your concerns and get her on board with some testing. If there is a problem, like dementia, it is best to catch it early because the medications that delay progression are effective in the early stages.
A Vitamin B deficiency can also result in dementia-like symptoms, so it is important to pursue testing. Proper testing could confirm fibro fog. Wouldn't that be a relief?
If you can't get your wife's permission, maybe you can let her PCP know the unusual symptoms you"ve observed so s/he is aware and has these in mind the next time s/he examines her.
You have my sympathy. This is hard to face, and terrifying. My husband was relieved when I took the initiative to learn more about his condition. I haven't regretted it.
I wish you and your wife the best.