once you have said what you need to say, and if he still chooses the way he chose, to move on.. then you move on.. you gave yourself a chance and gave him a chance work out.
you can talk to close friends, even though they can't help you, but it will help you, it is a psychological relief. just like you are talking here. there is a song which said "i can't make you love me, if you don't". But you can make yourself "unlove" him. (or undo the love toward him, with time, and with rationality)..
he can't help you, nobody can help you, but you can.