Sorry that you find yourself in this situation. You won't find a better group of people who are dedicated to try and get your M back on track.
First things first. Have you read DB or DR books? If not, then you have to do that ASAP in order to understand the concepts described here.
Now, going over what you just posted...
"We have had relationship problems in the past but it's nothing that can't be fixed."
That's your perspective. To her the conflicts seem that they can't be overcome.
"Yes, we did try extensive counseling until she stopped going recently."
Obviously there was something wrong if you went to "extensive" counseling. Whose idea was it to go to C? What marriage issues were there? Be honest and give us as much information as possible.
Post often and write down in your signature line how many years you've been married, kids, when you got the 'bomb drop', etc.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.