My husband is 55 and seems to have Frontotemporal dementia. No Dr. will verify it, but SOMETHING is clearly wrong with his mind. Advice?

Has he had an MRI or CT scan of his brain? Have you been able to see a neurologist? I'm thinking of something ominous like a tumor and an MRI would rule that out.
PCPs are taught "If you hear hoof beats, look for horses, not zebras." It sounds certain that your hubby's PCP is dead set on horses and not willing to consider zebras.
I hope you get your answers soon so you can begin planning.

there are some very good examples on you tube about frontotemporal dementia its sad but some doctors miss it my husbands doctors missed it at first but was diagnosis at 57 after being told it was just depression and getting lost one night and had a car accident I got more info on you tube than his doctor

Regardless of an official diagnosis, you clearly see changes and the symptoms. Have you been to Duke's memory care clinic, or similar? How about a gerontologist?
Does a new project for him require an investment of funds? If so, I agree that caution is required. Is there a trusted co-worker that can partner with him?
A friend of mine had her husband in a similar position. He had 3 car accidents and the last one totalled the car. It was less than a year old!
I urge you to read up on this disease and for the next visit, hand the office a letter from you stating all you have observed. This will help with the diagnosis. Good luck and keep us posted.

My wife has FTD with aphasia. It took us just a rather short time to be diagnosed. It really only took two visits to our PCP and finally doing the tests in his office to get referred to Cleveland Clinic for diagnosis confirmation and begin monitoring.
DW came home one day and said she got lost and had driven about 9 miles out of her way before recognizing anything and getting herself headed in the right direction.
One visit to CC and a scam confirmed that her frontal temporal brain had shrunken a lot and that there were other spots in her brain that were being affected.
Sadly she was too far gone for any meds to slow this any. She no longer has a drivers license, cooks, cleans, does her laundry, even eats differently. And so many other things.
It did took a neurologist at CC to confirm what was wrong with her. Now it is just wait and watch for other symptoms and health changes. And to do more to help her with her daily hygiene and dressing.
I wish you the best with this journey. It ain't gonna be fun.