Stay or go?

So my question today is "how much is just too much?" At what point does a mother, father, sibling say enough is enough? I don't know because I haven't been faced with addiction but in terms of just plain ole enough is enough, I guess I do know my threshold. My philosophy on the whole blood is thicker than water is pretty simple actually. I believe if someone is good to me, if they treat me with the respect and kindness I deserve, whether they are "blood" or not, I will continue that relationship. If, however, someone doesn't show me these simple gestures, they will bring me down and they are out. I really don't think just because you were born unto someone, that they can treat you poorly and expect a relationship with you. In my case it was a very easy answer. I didn't have to think very hard about removing this person from my life. It was easy. Do I ever mourn that loss? NO. I am fortunate that I have someone in my life that WANTS to be there. He cares, TRULY. If addiction is the reason for the treatment, though, I wonder if that makes it different. I don't know. I want to believe it does bear some weight but again, that isn't my situation. I wish for the sake of many, it were easy. I wish I could shed some wisdom of light to the people affected. I wish I could shake some sense into the one causing the pain. Because even when someone is DONE, in this circumstance, I don't know that it will EVER be done. It is just heartbreaking and unfair!