Hi JR - I agree with Jazz. It's not over unless you stop trying.
Just keep on giving mouth to mouth eventually she'll start breathing again. I am in the same boat. I have been feeling the exact same way. I just got to a point where I felt like I had to give her what she wanted. I told her that she deserves to be happy and thanked her for giving me the time and space I needed to work on my issues. I told her that she made the right decision in leaving and that we both deserve to be happy. By validating all her feelings I tried to take off most of the pressure from the sitch. Now that I planted the seed all I can do is sit back and see if anything grows. If not at least we gave it our best. The great thing about this whole experience I feel is that we are getting to know ourselves better and becoming better people for ourselves and our families. Knowing that, I smile inside whenever she gets me down. I feel good knowing I am actually working on my self and not running away like a lot of our spouses are doing. If most of us would have taken the easier way we would not be here.

Good luck my friend. I'm praying for all of us. BM