Who says you will never have a trusted best friend again?
Ellima, that is just not true. The "best friend" you had turned out to not be trustworthy or respectful or honest or...well, any of those things. I understand how you want that feeling back, and how sad it is to not be able to have it with him, but NEVER EVER doubt that you can recover, adjust, fix yourself, and find friends (best and otherwise) who will truly, truly be there for you. Who you can believe. Who don't put alcohol before you. Who really are interested in your well-being.
AH wasn't. Sad, but true. But out there are many, many more people you can invite into your life to see whether they can bring joy to you. If yes, they get to stay. If no, they get the boot.
Never doubt that happiness is possible.
I know this hurts, but it is the pain of removing this cancer from your life -- it will save your life AND prepare you for better times ahead. I swear it.
Have you read "Codependent No More" yet? Have you tried Al-Anon meetings?