I would rather go the traditional route and get put on some MS meds that have been proven to stop the progression of the disease.
If you find one of those, let us know! Seriously, there really aren't any medicines proven to be effective in stopping progression. If there were, we'd be all over them instead of continuing to progress. Have you had MRIs of your spine? I have questionable lesions on my brain and everything that is a definite is on my spine. I'm not alone in that regard either.
Just remember that the primary endpoint of all of the MS drugs was to slow the formation of lesions as evidenced on MRI. Statistically they were shown to drop the rate of lesion formation. However, that doesn't correlate with slowing disease activity at all. That was convenient, but since you have no lesions on your brain? I would seek counsel at another MS specialist at an MS clinic of at a university like Scorpion said. Many local docs will only 'catch' your diagnosis if it's typical. It sounds like yours is not. Many, many people on here are not either and they had to seek out someone willing to look outside the box. Have you done any Evoked Visual Potential stuff? When I was diagnosed they couldn't use my cranial MRI either, they used a combination of symptoms I was having, my spinal tap, the Evoked Visual tests and finally my spinal MRIs.
Even though you don't have much faith left in trying to find it through doctors, that is alas the only way you'll get a diagnosis as you say already in your posts. I would just keep searching and start at an MS clinic where they are used to not just dealing with rote cases of MS.
It's a real shit sandwich when you're in limbo like you are. Whether it's MS or not, what you are going through is hard to deal with. Especially since you don't have spousal or familial support; that has to be incredibly hard to deal with. That, in and of itself, would be enough to motivate me to not rest until I had a diagnosis. However, I feel you in that 5 years of trying to get it is just a monumental undertaking. Where to find the motivation to keep pursuing? That has to be hard and I don't envy that position. One thing I might try is to educate my wife on symptoms because what you describe sure sounds familiar. That is 100% me not telling you I think you have it. I'm just not qualified to say, but I will say that your symptoms sure SOUND like it.
I'll get pilloried for saying this by some, but if you're at wits end going the traditional route, you could always get an appointment with one of the DR's doing the CCSVI procedure. If it's obvious you have blood flow problems, they could be fixed and, for some anyway, it has really helped. For some anecdotally, a great deal. Shoot me a PM is you want any help getting an appointment to look into this. But it sure seems like you're running into a wall trying to get your diagnosis.
If you had only been searching for six months or so to get a diagnosis, I'd be chock full of things to try. But after 5 years it sounds like you've tried everything one does to get a diagnosis (spinal tap, MRI,etc) but I would make sure you do the EVP tests. If those come back that there is an issue, at least you'll know you have slow nerve conduction which indicates damage to your nervous system by SOME culprit.
One other thing is to see a physiatrist. Not a psychiatrist, that wasn't a misspell. They can do an EMG on you where they can see if you have slow nerve conduction and whether or not you have central nerve damage (probably MS or something), or peripheral nerve damage (something like a pinched nerve or something like that).
Hang in there brother. At your age you have to be scared shitless. I hope you can find some peace of mind and I sure hope you get the support of your loved ones!