Need Advice on an Ex-Girlfriend who still likes me
We went out for about 9 months, and I broke up with her in September. It's been 6 months since, I've never led her on and made it clear that I had no interest in getting back together, but she still hasn't moved on. Normally, the advice would be just to break all contact with her, but it's one of those situations where we're both in the same group of friends (dead giveaway that we're in high school) and I don't want to ditch my friends just for the sole purpose of spending less time with her. She's somebody I still care tons about.
She has depression and is currently in the process of being treated for that. She's flat out told me that if I were to get another girlfriend, she would commit suicide. I know it's not good to get blackmailed like that, but if she did, I'd be devastated.
Any advice for this general situation I have? Thanks in advance...