ssmguy,

Let me ask it a different way. If there was a want or need that your wife had that you could satisfy for her without harming yourself, and to go without it caused her discomfort, pain, feelings of rejection, etc... Would you simply say "I don't feel like doing it, I will do it when I feel like doing it"? Or do you think this is selfish?

I think people don't understand what their doing to someone unless its done to them.

Perhaps you take away one or a couple of important functions away from the wife, just to illustrate? Don't tell her.