You are very lucky to have a spouse, especially one that is supportive. I was unlucky enough to be single when I got ill, and have never had the energy to maintain my regular friendships, much less date.
Just an idea, but perhaps have your disease write your wife a letter. I know that sounds crazy, but I also know that trying to explain exactly how hideous it is to be sick is a hideous task, and most of us begin to feel whiny or pathetic after half a sentence.
Having your disease "explain things" not only emphasizes the fact that it has its own mind, so to speak, and exists headstrong and unapologetic, but it also helps to show her how and that it exists absolutely without your consent or approval and does things TO you whenever it wants, how it wants. The disease in its own voice can reveal how much it is a greedy and jealous companion. It does not want to share you with anyone. It has no respect for plans, pre-arranged events or outings with loved ones. Well, you get the idea.
What you are going through shouldn't "hurt" anyone much less your wife, save for in empathy. It is the nature of the illness that there is no such thing as doing something "little" or small whether to relieve boredom or to salvage friendships that may be disappearing before your very eyes. The disease won't allow what it won't allow. It isn't your fault, of course, and she will understand that.
Let us know how you get on. I hope things get better for you.
Have Fibromyalgia, Polyneuropathy, Hep. C, rheumatoid arthritis