Why question whether or not to give your addicted boyfriend another chance or not?
Because you are at a place in your life where you have the independence and financial and emotional health to do so; and because you are not yet in so deep that is terribly difficult to unwind the strands that bind you to an addict.
If you went to the racetrack and you had the chance of betting on a horse that had a good solid history of winning races, or one that had no history of long term success and had the odds all against them, which would you choose? And most important, what is your reasoning for choosing one over the other, and what does it say about you?
What people are talking about here is the amount of risk that you are willing to incur, and to invest in by continuing a relationship with a man who has a major and self-imposed handicap that will require him to apply fierce self discipline for the rest of his life if he is to surmount it.
Your girlfriend, as the daughter of a crack addict, had no power to choose or not choose her father, and she evidently suffered greatly. I think she is just trying to share her experience with you.
If I were in your situation, I would not be defending my boyfriend or wondering how I could be supportive because nothing you do will, in the end, make a bit of difference. What he does or does not do is solely a measure of his strength and commitment to health.
I would be asking myself why I was attracted to a life situation with such poor odds for health and happiness.
ShootingStar1