Hello there! I can definitely understand why you would be so frustrated, and it boils down to this: if he can push himself doing the activities that he wants to do, such as hunting, fishing, boxing, and etc., then he should be able to help you do little things around the house occasionally. From what you say, it seems like he may be using his disability as an excuse to get out of doing the things he does not feel like doing. I am sure that he does hurt, but making you happy and keeping his marriage healthy should be one of those things that he "wants" to do, and it seems a bit unreasonable that after 12 years of this pain, he wouldn't find some way to cope with it for a couple hours a day. You are his wife, not his nurse. If he is unresponsive in your discussions with him about this, then perhaps it's time to consider a trial separation? This is no way to live your life.
I wish you the best of luck. :-)