That took a lot of courage to write - even if it is to the anonymous audience on the internet.
You are not alone. Your situation mirrors mine in all but your disability. I am not specifically disabled but am genetically predisposed to obesity. I am working VERY hard on losing fat and gaining muscle with excruciatingly slow and very limited success. So, though not so difficult as you, I probably understand better than many the frustration you feel. It is incredibly difficult to work SO HARD and other guys in the gym surpass me with seeming ease. Like you, I try to make the most of what I have got - and I admire that about you already.
Well, I just wanted you to know that you are NOT a weirdo, that there are a LOT of guys that feel very similarly to you. I suspect that more guys are turned on by muscles and muscle growth than will openly admit to it. Why do you think that characters like the Incredible Hulk are still so popular? Many men feel as we do to some degree.