First let me say... YAY. that probably sounds mean, but you can use every bit of that anger to detach. Tell yourself over and over again "i deserve love. I deserve a loving R. I deserve better than he is giving me right now. I will make myself happy" maybe eventually after he pulls his head out of his a$$, he'll give you what you need, but right now, he just doesn't care.
If he texts/calls you on something trivial, ignore it. for exapmle "what are you doing?" "who were you with" "why haven't you called"
If he needs something specific "did the phone bill get paid" (not sure what he'd be asking you that even matters at this point, but anyways...) Don't speak with him. Leave him a message or txt him. Yes or NO. Part of it is also keeping things brief and to the point.
the idea of you being happy and upbeat is to show him that you don't need him to be happy. Do you want him in your life? yes, but will he destroy you if he's not? No, or at least he doesn't need to know it right now.
Anything you can answer yes or no, do that. Anything else? keep it short and sweet. I'd avoid actually talking to him though because he might trigger an emotion that you can't control or think about and you might not be happy with the way you respond to him.
If i can't fall in love... I'd like to fall in chocolate! ~ Author Unknown