There is an assumption being made by the OP that anyone who remains in a relationship with a loved-one suffering from addiction is doing so out of fear. For me, this is certainly not the case. I have no fear of living alone if it eventually comes to that, I am staying with my husband because I love him. Addiction is not a choice he made, it is a terrible fate which has befallen him. If he had developed schizophrenia, or any other mental illness, I would not say "well, this could affect me negatively, so I better 'let go or be dragged'." We have worked together, as a team, to overcome many difficulties in our past, and I don't see why our current situation should be any different.
I think it's important to remember that everyone's situation is different, and no one has any right to tell others what to do. I try to speak only of my own situation, since that is the only one I know, and let people make their own decisions for themselves.
My $.02,
Daisy