Oh, and I forgot to add -- in a subsequent comment, the OP mentions that he had already told several friends, who were all supportive, causing him even more shock when his wife did not respond the same way.  What I wanted to say to him:

(1) Of COURSE it's easier for friends to be supportive; they have no reason to feel betrayed or deceived as a spouse would.  How stupid are you?!

(2) So now your wife knows that you not only put off telling her for a long time; you didn't even give her the respect of being the first person to hear it from you.  She was lower priority than your friends.

Makes me want to join the group and comment. I hate the "You're so brave" comments. In reality, it should be "You're so selfish." because, well........, it is the height of selfishness.

ADSJ,
   Yes, then she'd get the "s/he's still the same person inside" crap.  To which I always say, if s/he's still the same person inside then why does s/he have to transition?  Why is it always the spouses who are told to be willing to change their entire sense of themselves and the marriage and not the person who wants to blow everything up?   If you're still the same person inside, then just keep living as the person you are.  The fact is they AREN'T the same person: they want nothing more than to be an entirely different person, down to the their biological sex.  They want to dress differently, act differently, have sex differently, take a new name, get new friends, and abandon past pursuits and take up new ones.  How, exactly, is that evidence of "the same person"?
   Most people haven't given the whole trans thing any more thought than they would to an autonomic reflex--until something goes wrong with their own.