I see nothing for you to regret.
You did do your best and it was good enough but if your bf is an active CG it would not have been the enablement his addiction demands.
You could be right in all your thinking but of course I cannot comment on that which I don’t know. Keep up your standards and your goals and you will find someone worthy of your love.
If he is embroiled in addiction your bf will not appreciate your care at the moment – but if/when he changes his life he will be glad that you are not part of the wreckage that he will struggle with. I have seen the guilt caused by an addiction and it is terrible for a CG to live with, so go and have a good life and use this experience to make life better for you and those you are yet to meet.
Well done coming her and sharing your story