Aj, before my H left me, we went a period of almost 6 months of absolut madness. He was angry at me about anything and everything. I was walking on eggshells so much I turned into a scared 3 yr old kid. He was trying to base his need to leave (and probably be with the OW) on facts for his mind to accpet it as moral. The month after he left I GOT MAD. I got VERY VERY mad. Said things I regretted while he was laying low and only responding to my anger. After that, I slowly started to accept the sitch. I think this is a very common way emotions cycle in these cases.
What DID help me, was to stay away from him as much as I could. Everytime I saw him in the beggining, was like hitting a fresh wound by accident. No matter how prepared I thought I was, I always felt like sh!t in the end.
Regroup. Her moving away, no matter how "cool-controlled" (lack of the right word) things happened, is a turning point, very painful for you.
I would actually, at this point, consider if I would go to the mountains with her. The timing maybe off unless you can really act as if when you are there and use it to bring you closer. You think that is possible? K