i agree with anvil, is there a way that you can find something to do that will keep your mind occupied, try not to think about him at all, for a little while, read a book out loud, go for a walk, start a project like maybe clean a closet or something that you can do to block out all thoughts of him just for a little while. you'll find that the more you do this, the less you'll have to. just like anvil said, you have to do the foot work if you want to feel better.
mybe its time to except the fact that he is an addict and thats how addicts acts, you can't change what is, and meditating on what was is only making you feel worse. most of us have been where you are and do understand how hard it is and how much it hurts, but at some point, we all came to accept that what is, is, and that there is nothing that we could do but try to move past what you know it to be now. you have to began to think about not what you are missing but what are you gonna do now that it is missing. i'm praying for you. try to take the focus off him and put it completely on you and decide what are you gonna do if he does not go back to the man you pnce knew. sorry that you are going through this but if you want a change in the way you feel and the way your life is going, you may have to be the one who do the changing.