I dont know where to begin. I am so, so sorry that your world has been shaken up this way. I am certainly not an expert on saving a marriage (you have seen my many marital struggle posts here, so I would probably be comisserating with you more than offering helpful advice). I have a lump in my throat about the going back with her part.
I am going to say a prayer tonight that your DH realizes that he still wants to be together and you two can begin to rekindle your relationship.
So what would I do in the meantime, while DH is thinking it over? I would do just as you are....lean on your friends, hug your kids, think about those practical things that you can do to provide yourself a greater feeling of self-security, no matter the outcome of his thinking it over. It might be saving a bit of your grocery money in a cookie jar each week, making sure you have your own line of credit, making sure you have access to all bank accounts and credit card numbers, etc. I hate to sound so darn practical, but that is the way I am. Getting a handle on the practical aspects makes me feel more confident about the parts that scare the living daylights out of me.
I hurt for you. I wish we knew each other in real life and could get together and remind each other that we are much, much stronger than we realize. We have what it takes. no matter what obstacles or hardships we may fear and/or face.
Stay strong, my friend. Were all here for you.