Sorry to hear about your situation. It strikes me as very odd how your S just seemed to flip out and decide to leave.
If she's not responding to you then there's nothing you can do right now except focus on yourself. Make yourself happy so, if things don't work out, you're not sitting around moping and hoping your S will change her mind.
I myself found it very theraputic to write down a list of things I've always wanted to do and am commited to doing them as quickly as I can.
Enjoy being by yourself for a little while. You can do what you want, when you want. Yes, it's always sad when things down work and even more sad when you don't know why but you don't have to stay that way. Get out, meet people, do things. The possible (because nothing is certain) end of a marriage isn't the end of your life.
