How to deal with a boyfriend-obsessed friend?

My best friend in the world is pretty much gone, this is a long story so bare with me please. She has been my friend for 11 years, and we've grown very close until now. This year she has a boyfriend, and it seems like everything is about him and its really annoying. For example, she has extreme PDA problems, because she makes out with him in the hall in school every single morning. I hear people talk about them all the time, and the thing is I'm starting to agree with them. If she's not talking about her boyfriend, she's with her boyfriend. She thinks she's in love, but she's already broke up with him once, because she's "in love" with 2 other guys..... that she met online....she's 16.... and has never even met them. This guy is annoying too, his facebook status's are always "wants to be with his baby girl so he can hold her and kiss her" and has made it PUBLIC by making it his status, and writing on her wall that "he wants to marry her and make a family with her" ...she's 16!!!!! It's not fair to me what she's doing, and she's going to get hurt in the end. We're part of our school's talent show, and she brings him to rehearsal and we get nothing done, and I'm not going to work on our routine alone, I have a lot more to deal with than her.... what do I do???