You've depended on him so long that he's come to depend on you in return, and now you've found it in yourself to step away, he's stumbling. Eventually he'll adjust, and either you'll choose to reconcile with him on your own terms, or you won't and he'll have learned to stand alone.

At best, neither of you are to blame; at worst, you both are. But tell me why it's useful to apportion blame at all.