i realized that dolly was saying what i kind of wanted to say. in my opinion, maybe you might want to take a deeper look inside you to see why is it that you seem to be so afraid that you'll be rejected or abondoned, maybe a therapist can help you come to grips with what maybe an underlined issue surrounding your fears.
i also believe that it takes time and conscience awareness to change habits, try not to beat yourself up. maybe if you haven't already, try to recognize and accept what might bring on these feelings, you may decide that you won't allow yourself to think the thoughts that trigger those feelings. if just so happen you find that you can't change the thoughts, you may find yourself trying hard not to hear whatever you listen to that may trigger the thoughts, either way, in my opinion, focusing more on you and less on whats going on with him, maybe a good place to start.
it took for me to realize that no matter what i did or did not do, if he wanted to use, then he'll use and if he wanted to leave me, there was nothing i could do to stop him, so i decided to take care of me and what i needed to do to make my life better and turn him over to my hp and allow him to lead him where he needed to be. still praying for you