My friend is absolutely obsessed with her new boyfriend?

[Headache]

I was in love with my best friend for 4 years. Then 4 months ago she began dating this guy. It tore me apart but I decided to be happy for her. But she's gotten so desperate all of a sudden. They've been having problems and she uses me as her shoulder to cry on. She 'bad mouths' him, I tell her she deserves better, then the next day she's all over him again. She's been posting lots of pictures and statuses on Facebook to him which all seem really desperate because he doesn't really respond to him. I've watched her stalk his profile over and over again. I hate to see her this obsessive but she won't listen to me because she's besotted. Is there anything I could do to save her from this desperation? Or should I walk away?

[Ashamed]

You can't save her. Trust me. She will have to figure this out herself.