Hi Jeni26,
You say that you are absolutely certain that if you hadn't drunk again he wouldn't have. I appreciate it must feel like that, however I question whether that is something you can be absolutely certain of. From what I have learned about alcoholism and addiction there are very few certainties, relapse is common and we cannot think we caused the actions of another.
You could have abstained and he may still have picked up again, there is no way to know.
However it IS his choice, just as your sobriety is your choice.
It seems like holding on to the though that he would not have drunk if you didn't is torturing yourself. And that will not help anyone.
Sending love.