You proceed from a false assumption. You cannot be best friends with an ex-fiance. That option expired along with the engagement. Your offer has been counter-offered with the "God's will" proposal, which is the ultimate cop-out for a person who doesn't know how to help you let go, or who has become overwhelmed by life's challenges. To that end, do not expect him to chase you down, or reply in kind to your continued invitations. God's greatest gift is free will, which is what he gave his Son for, why Jesus allowed himself to be crucified. Check out the theology on that one, and you'll see that your ex-fiance is using the scapegoat theory on you, which is the same way that early Roman Catholocism attempted to place the blame for our failures on God in order to build a following. Do you really want something like that chasing you? You can see how it's sucking the life out of him, and I suspect by what you say that you are beginning to feel it too. You don't need his permission to be his friend, but he is not at peace with himself now, and so will have none to offer you. Count youself lucky to have been able to love as you have and take it with you as you move on now.