I separated last August and STBXH moved out in the September, my children are 9, 6 and 4 and have also been amazing. It is amazing what they can take in their stride when perhaps they knew Mum and Dad weren't happy before and when Mum and/or Dad are answering their questions and keeping them informed on what is going on.
I was the one that ended my relationship after years of trying and now 9 months later I am glad that I made that decision. Now that I am not living in that awful relationship I can see how bad it was and life is so much happier now. I don't dread my ex coming home every night, I don't walk on eggshells anymore.
I also second the suggestion of exercise, I took up karate and it is brilliant. I can take my frustrations out on my sparring partner once a week 
Also, all the things I was made to feel were unachievable, I am managing to do on my own steam (doing up the house, going to college in September etc). I didn't realise how much of a negative effect my ex had over me and now I am getting the spring back in my step.
Don't get me wrong, it is hard at times and sorting out the finances/divorce is not easy but is a hell of a lot better than the shit my life had become.
Be strong, be kind to yourself and don't let the bastard get you down!!!!