My advice: Do not stay friends! It is too tempting to fall back into old patterns ... read what you wrote at the beginning ... "good relationship" ... do you still see it as good. That is your old self, the one that is clinging on. Far down the line, when you have gone through grieving your loss - which you no doubt will have to go through, to let go and find yourself again - you might be able to be friends with him again. I would only do it when you are at the point you can say 'Breaking up with him was the best thing that happened to me, because look at where I am now'! Be strong!