Hi, Wazbamhat.
It is quite common for spouses to be unhappy with the donation--even if they don't deny you permission to do it.
I agree that offering various factual materials is a good idea. Another one might be to see if you can find him other donor spouses to talk to.
But...some spouses really don't want to hear too much about it. So, try to sound him out, and get some sense for how much info he really cares to take on board, or whether he prefers not to discuss it. People have different ways of dealing with this kind of thing. Preserving your senses of humor would be a definite plus (if I can think of any good kidney donation jokes, I'll try to post them).
Good luck, Snoopy