You answer with, "yes", "no", "maybe", or "I'll have to think on it".
"I don't have time to talk." "I'm busy." Is another good one to use about 5 or 6 times before you say, "I really don't want to talk to you anymore." "GET THE POINT!"
Its all really simple. You just dumped her. No one likes being dumped. Maybe you heard the lines on TV, "you didn't break up with me I broke up with you." Well its true: Even the cheaters don't like getting dumped. Once they have that sense of control it is hard to give it up. However, in reality, you have more control in this situation then you ever taught you had. I am glad to see you realized that.
What you wrote was good. I personally found that giving up without saying to many words about it was enough to wake Sister Mary Elephant up to realize that she needs to start acting and talking to me like an adult and a partner. I won't discount yours or Gucci's or Rob's speeches, I just didn't have enough emotion and try left to care.
If someone asked me to read what you sent your wife, I would think they just got dumped with a 'I Hate Your Guts' thrown in for good measure (I don't even want to be your friend).
People respond to that in a couple of different ways. First one off the top of my mind is the go out and get laid in spite. Or they try and turn it around and make you out the be the bad guy and the weak one and use your codependency against you until you back down. Or they may feel a sense of relief that the inevitable just happened and they didn't need to be the one who did it. Or deep down in the pit of their stomach they may begin feeling loss and despair and realize there were changes they could have shoud have made before this came to a head.
But, honestly, what does it matter how they feel or what they do. To be cheated on once is pain enough; to have it happen multiple times is complete uncaring about their "partners" emotions and sense of self worth.
After reading and questioning a few people on this site that are in your wife's position its obvious the next important move is to file for divorce. Let them know in bold capital letters:
I AM DONE! I HAD ENOUGH! THIS CANNOT GO ON!
Enjoy your live because it was the one your were given. If someone cares enough to join you they should not be making your life a miserable hell to be part of it. That is a realization that they need to make now. Bravo.