Do your thing Pussyhunter.
It sounds like you really care about her, nothing wrong with that. However, to quote the great Wu Tang Clan "Protect Ya Neck" son. I have a buddy who's brother met a girl who was a SW with a white powder problem in rehab while he was working there as a counselor. When I first me her, I thought, bad move. To my surprise, they got married! To my even greater surprise, they now have two kids and have been married now for 18 years. I see them from time to time and they both seem very happy. My buddy tells me there have been no issues regarding her former lifestyle or drug use. So, it can be done. Do your thing man.
Now, I've read the responses to your post and can say, some are accurate with regard as to how this situation ends a majority of the time. However, some have haterade sprinkled all over then. Like damn, is your life so fucked up that you can't give someone a little encouragement instead of trying to shit on his happiness? You only live once, enjoy what and who makes you happy. The funny thing is I know "regular girls" that are bigger hoes than many SW. Shit, chicks talked about in the non-pro section here are probably somebody's girlfriend.
Anyway, PH ride this shit till the wheels fall off.