Hehehe for all you know, he could be young, handsome, fit, successful with a beautiful home as well LOL.  Doesn't hurt to ask nor are these desires / attractions endemic to"average" people as they require one to think outside the tiny little box of "programmed normality"

Interesting story and yes, these things usually develop when we are very young, they are what they are, are not going to change so the trick is coming up with a means to satisfy and be happy with them. 

This seems to split into two different areas of interest as well.  One is a visual / erotic attraction / desire, such as my own where i simply love the look, where those sharing will generally want to see or lose a single limb with consideration to minimizing the actual disability involved.  In the case of my lovely wife the contrast between her totally empty left side and her single magnificent arm and leg is absolutely exquisite to my tastes and she always seems to accomplish 10 X more with 1/2 as much as anyone else i know which i'm very happy with as well.  On the other end and as you state there seems to be a "bondage" aspect involved and consequently an attraction to the actual disability involved as well, where the person ends up wanting to lose much more, often extending to all 4 limbs.  In your case there seems to be an enormous erotic component to this as well as with my own attraction and in the case of other Amputee Wannabes it's just the way they want to be. 

Some interesting diversity among the common interest.