How long should you wait for a guy?

Well you don't necessarily need to wait for a guy. You could be the one making the first move :P I mean I know it's more sweet and everything if the other person makes it fist but, they might be thinking the same as you and just waiting for you to make the first movie instead. I'd say just go for it :3

Have you considered making the move first instead?

Fuck that. You are not obligated to wait for someone if they don't show that they're going in that direction. Knowing they love you is one thing, but knowing they will eventually be yours is another. If you've waiting for years and there hasn't been any progress, I would suggest moving on. It doesn't sound like they ever really plan on people with you, and are possibly just using you.