you've answered the problem yourself, right here. there's only so much you can do. there are things people can only learn through experiencing them themselves, and maybe more than once. i've had more than one female friend with the same low-self-esteem-so-i'll-sleep-around-to-try-to-find-some problem, and as much as it hurts to watch, all you can do is offer your advice. your friend is the only one who can change her situation.let me tell you a story from my past that relates. i had a friend in high school who was doing heroin, and it was tearing me apart. i couldn't sleep, i cried a lot, and i'd miss school 'cause i was so worried. i had nightmares of him dying; i even was afraid that news would come of him dying, when the telephone rang. i went to the school counselor and told her about my friend (who went to another school), and asked what i could do to help him, as i'd tried to tell him how bad heroin is and how it can easily suck people in. but the counselor pointed out that i was obsessed with my friend and his problem, and i needed to address that. my life was a wreck, and it didn't have to be. and people on an addictive drug like that can only be helped if they want to be; my worrying wasn't doing anyone any good. i eventually detached enough so that we could have a healthy relationship again, and my friend kicked his habit (thank god!). but he only could do so because he really wanted to and was dedicated. your friend has to want to make changes, as well.