Bella,
I know that it hurts when others point out the negative, but this is coming from those who understand the pain of getting burned.. they would wish for you to run the other way, spare yourself the heartache and pain that may likely occur.
People do recover! Not all, maybe not the majority , as I understand it. But if you want to give it a go, then that is your decision. If it gets too painful, you can exit, knowing you tried. Please take care, If I may get personal, to wait on children, as that will only add an innocent child to a frightening situation. Like your friend... I would guess that she has experienced great pain from having an addicted father. She spoke from a place of pain. and does not wish the same for any one else, especially a child, as she mentioned. If she is a BF, forgive her, for her fears are legitimate.
Your boyfriend may recover, and as you said, it is not ever cured, and they must always be vigilant in protecting their recovery. For me, it is like building a house on unstable ground, always the chance that it can go bad.. But you are the one who has to decide, and you are smart enough to take care of yourself.
I wish you the best! and your boyfriend too.