My suggestion is to listen to the board and the vets. Wonka and Caliguy have been great resources for me.
#1. Get control of your emotions - NOW. Wash your face with cold water, run, anything but your emotions are controlling you now and making a bad situation worse. You control your emotions. If necessary, go to the doctor for some anti anxiety or depression medication. They will help.
#2. Let her do her thing - no pursuit - none She will quickly realize that life without you will not be so rosy. Let me realize this for herself.
#3. Spend this time working on yourself, self help books, going out with friends, anything to get your focus off your situation. I know it feels like the end of the world but it is not. Try to focus on what is going right in your world. You will notice that many things are going well, look at them and be grateful.
#4, Man up - act with confidence, purpose and self respect. That will be key. Do not tell her what you are doing or why, just do it.
Keep posting friend and remember we are all on your side and have been in your shoes.