You aren't alone, I struggle with many of the same issues with my hubby. I wish I could say I've found answers especially in reference to where action or advice would differ from that given to family of alcoholics with mental health problems.
I can understand how frightened you must be, when we were just friends (before marriage) - years ago, I feared for my husbands life. I detatched lost contact and thought he was most likely dead for nearly 10 years. I never looked for another man.
He came back years later and much better in himself, the improvement was astounding. Since then I've often wondered whether knowing what I know now if I'd have done things differently all those years ago. I think the only thing I would change would be to nag less, beg less, try and stop him less, none of the begging ever worked anyway.
Whatever happens now,then and in the future all I can do is act to the best of my knowledge and belief, it will always be flawed no matter how much I read or learn. The best of scientists disagree with mental health so I've accepted that there is no real chance of me finding ultimate truths - this means I will always be likely to do the wrong thing sometimes.
The other thing I try to accept is that even knowing my actions can have a bad effect sometimes, it isn't my fault when he's ill. Sometimes I can do something which shouldn't cause any harm - depression or anxiety means it does cause a problem BUT that's the illness not me and often not him.
That he's at risk ISN'T your fault - you know that don't you?