Spook, I am so sorry.
I think you are doing the right thing. Let him go. His being at home with you is making every day torture for you. I think there is still a chance he will want to come back but it should only be if he is coming back to wholeheartedly commit to you. Don't accept anything less.
Your extremely difficult task now is simply to get through each day, giving yourself time and space to allow the hurt to heal, however long it takes. Eventually you will find yourself positive and making plans for the future. But first is the painful time of coming to terms with what has happened.
I see it as a long hard trek through enormously difficult terrain where you will be injured, exhausted, confused and lonely. But at the end of your journey will be a new peace and a better place to be. That place is there, never never forget that. And you will reach it. But it will take as long as it takes.
You and your children have each other's love, there will always be a cuddle for you there. I know that is not the same, but it is more than some people have. You still have a beautiful family, your dh is the one who is alone for now.
You will never be alone in facing anything. You have your kids and you have mumsnetters who care deeply about you and will not let you make this journey alone. Lean on us for support.