Trumphy, you could be me a year ago. That stage where you have finished it but still living together is definitely the worst. It is like grief, but he is still there and the wounds are still raw. Once he goes you will feel a huge surge of relief, the tension will disappear and although you will still have to grieve for the future you won't have any more, you will be able to envisage a new life.
Don't take to heart the comments about how you should never have got married, it seems that some people have to rewrite the past in order to justify their behaviour.
There's no point either of you regretting the past, you have your lovely DCs and I'm sure there were happy times, but its only natural that at the end of a relationship, those things are forgotten.
I can honestly say a year on, I wish that it had happened years ago. We are both much happier apart, the DCs have coped brilliantly (in fact they see more of him now than they did when he lived here) and I have met a lovely new DP who treats me as I deserve.
Once you come out of the fog you will see how much better your life is without this man who never really appreciated you and enjoyed putting you down to make himself feel better. Yes, there's a possibility that he may meet someone new and he can criticise her cooking and make her miserable then. When you're ready you may meet someone yourself, but for now, the most important thing is to keep stability for the DCs and to start finding yourself again.
You will get through it and when you look back you will be surprised at how strong it has made you. x