I know there are some people who will treat you like you are Dfd even when you have just faded away, but I think that people who really love you will be (secretly) relieved that they are still allowed to associate with you.
I have the same situation as you in some ways, oompa, in that my parents are old and I really want to minimize the hurt to them. I don't know if this is the best way to deal with it, but in my case I chose to avoid being Dfd so as not to force them into a difficult position. This means that I can't be clear with them about how I feel about it all. Usually I just refuse to talk to them about it. I make it clear that the decision is mine alone and that I will not be persuaded otherwise but I won't get into discussions about the 'whys'. I've told my parents that I am sorry for the hurt to them, and that I almost wish I could go back just to make them happy, but that if I did it would all be a lie. I've reassured them that if I ever decide to go back (not likely!) they will be the first to know.
It's a hard one: you've got to be true to yourself, but try not to hurt your loved ones. EIther way it's going to be painful. But, I think if you can find a way out which causes the least offense, you leave yourself in a situation where you may eventually be able to help the one's you love to escape as well.