Snodderly is so right, you have not failed. Your H is a very lost soul right now.
Tuesday, do what you have to do for you and your kids. That is what is the most important. Make sure you are protected. Your a smart woman and I know you will do great.
As far as letting go, it's like a death in the family...we have to go through the emotions and we will heal.
You have been through the wringer in all of this and I hope you find some peace in your life.