I am sorry to hear of the grief you are experiencing. You lost your husband through a choice he made and I can feel in your words just how much it hurts. His soul is troubled and confused, and I hope and pray he will attach himself to people who will build him back up as a person from within and steer him to God who can heal his brokenness.
My guess is that he had questioned his own abilities for quite some time and reached his limit. It's likely much of what he felt about himself and his world around him had more to do with his mental health and lack of life satisfaction than with you. Maybe he knew the impact all this would have on you but felt he owed it to himself to escape any hint of commitment and unconditional love because he knew he was not capable of being that loving and giving person.
As you may have already been told by others, on this website or by close friends, it is critical that you also attach yourself to people who are in a position to help you. Talking with a Christian professional counselor will help you release this indescribable emotion you carry. Is that a possibility? I know it might seem impossible to implement a plan to move forward in your life, especially becasue of all the pain in your heart, but God designed fellowship for that very reason. He uses people to bring restoration and hope back into our lives. Don't be afraid to reach out for help.
Is there a women's group at your church? Surrounding yourself with women who love Jesus can stand strong with you and pray with you. They can help build you up as a person, a woman, and a child of God. It is a process I know, and yet you need others to help take you through this journey to become whole again.
You have both reached a very low point in your life and are faced with making new decisions. Please reach out for help and attach yourself to individuals who know how to love unconditionally, and who know how to listen. Ask around. Ask God where to go and what to do. He knows all of your days before any of them will come to be so He knows what today and tomorrow will hold. Prayer takes us to a place of faith and trust, the two most necessary anchors for our souls. I encourage you to ask people to commit to pray for you. Let God begin to heal your hurting heart and show the you path to take. He is faithful.