hummingbird,
I know we've talked a lot about this issue. Therapy or anxiety drugs won't help. Talking to you about how bad he's feeling won't help him and is only making you sick with worry.
There's a term in the recovery community known as "the gift of desperation". When someone is desperate enough, they'll get clean. His girlfriend leaving and work anxiety are all trivial matters in comparison to his vicious disease. If you try to ease any of these, you're only making it easier to avoid desperation and continue using. With how resistant he has been for so long, losing a job and a girlfriend might be what needs to happen. You're providing the illusion that his life is manageable. He needs to realize that it's unmanageable.
Like tomsteve said, you're loving him to death, and your codependent behaviors are making both him and you worse off. You should go through your post history and see the patterns. If nothing changes, then nothing changes.
At this point, you need to make a decision and stick to it. You can call and talk him through work anxiety and losing girlfriends and being depressed for years if you want. Eventually, you'll become just as sick as he is. He's made his bed, and now has to lay in it.
Sorry to be blunt here, but these are things you need to hear.