I agree with CJ, and neptune and pretty much everyone who has responded to you. We are not born knowing how or what to make of our various relationships, be they at work, home, or in the neighbourhood. That takes time and education.
Shame has nothing to do with failure. How many times did you trip over your own feet trying to walk, or fallen off when learning to ride your bike? Failure is part of life, if you even want to call that failure, which I don't. You just weren't successful in the beginning.
You have done nothing wrong except choose and support a man who's not on your page. Everyone on this planet deserves respect, but we each have to realize that for ourselves... and then to expect it. He's not respecting you. Do you respect yourself? I am so glad to hear you're interested in therapy. That is the first step. Good for you!
There are many resources out there that you can read online, as well.
I also want to ask - why is he is buying a motorcycle if he's disabled??
I support you 100% and hope you keep us updated with your progress.