Then burn it.
It is totally cathartic to do this with a pen and paper.
You can do exactly the same thing when you type it. It doesn't have the same affect on your system as watching the pieces of paper burn though. I've done this exercise numerous times.
In addition, I have deleted many a text. I have gone to my contacts and just looked at a number and decided to NOT hit send. I have hung up a phone just before it rings.
It's good for the soul, good for the heartache, good for the anger and good for you. Go ahead...it's your turn now.
It was SO totally sent!