My dear POAndrea, I am so so sorry for the tragedy you are dealing with.
What is most important is that you understand - and believe - that you, singlehandedly, could not change the course of your husband's life. We all like to think that we have power to make someone else's life better, but we really don't. Once you start into the "if only a half an hour sooner" frame of thought, it takes you to question so many "if only's" - "if only he hadn't been an alcoholic", "if only he hadn't had a cancer diagnosis", "if only he had healed enough emotionally to have coped with this", and that just goes on and ont and takes us to desperate places. The real choices were his, and it is devastating and tragic that he chose what he did.
The truth, as many of us who love addicts and alcoholics have to accept, is that
We didn't cause it;
We can't control it;
And we can't cure it.
That doesn't in any mitigate the grief, and the profound loss, especially when your future together was more hopeful than it had been. But it doesn't make it your fault or your responsibility that he died.
I am so so very sorry for your loss.
Take care, and be gentle and loving with yourself. We are here for you in any way we can be.
May God be with him, and may his soul now be at peace.
ShootingStar1