Why is my ex-boyfriend's girlfriend doing this?

This is really high school stuff, (im no longer in high school) but I would like some opinions on why someone (my ex's girlfriend) would write on peoples facebook saying 'omg, your friends with 'kayla'. Your so much better then that.' This person wrote on 3 of MY friends wall (she became friends with them) asking them why they are friends with me. I have not talked to my ex since Feb. I mind my own business. I dont care about him OR her, because all they do is lie and cause so much drama! Well, the first one I let go, but when 2 more showed up on 2 other friends walls with the same saying, I gave her alittle phone call. I told her that she needs to stop talking about me, and saying stupid stuff! She keeps telling me the same lines over and over that im crazy, but im the one who has 700 friends, to her 50. Shes told me that 2 of my good guy friends think im crazy. ( she tells me everyone thinks I am crazy. So I called them and asked them why they said I was crazy, and they said they NEVER said anything of the sort, and that they dont even talk to her, that shes the one that talks to them. She asked them to be friends with her. My cousin has a class with her, and my ex's girlfriend told me that my cousin talks sh*t about me. My cousin said that wasnt true, and that she would never talk sh*t about her relatives. Today his girlfriend drove past my house, (my mom saw her) and she flat out denied it! Then she said that when my ex is home, her and him drive past my house all the time. And I asked her why....and she said that he just likes to take different routes! The only person who is crazy is HER! She hasnt grown up one bit, since she was 14. 'Nobody likes you'...'your crazy', etc. I have SO much hatred for her because all she does is cause trouble. I told her that she has been so jealous of me from day one...and she laughs. Its true. My ex cheated on her with me for 2 years. (we only did it 2 times though) and she doesnt even believe me. I told her again, and she laughs saying that im crazy, and its all in my dreams. 3 of my guy friends have come up to me asking me if its true (I never told anyone, except my mom) I asked 1 of them where they heard it from, and they said that 'pj' told his whole car group that! Now one of my very good guy friends wont even talk to me anymore because he cant believe I would stoop that low. He told me im better then that, and I told him, 'yes I am. I realize that now.' I wont even get into my whole story with my ex, but if my bro ever came face to face with him..he told me he would most likely go to jail,(he wouldnt be able to control himself) because of everything my ex put me through. I have such anger, and hatred for her that if I had the chance..I would want one good hit at her.....but I cant since shes a minor and im not.

Why cant they just leave me be!! Everythings been so good for the past 4 mos, and now this!!

Sorry, I just really needed to vent!

Hmm this sounds really familiar, sorta like me and my Ex's and his so called 'good friend' thats a girl. My Ex and I were together for 4 months, She coems along I find out from her used to be best friend that her and my ex talk smack about me. What do I do? I've had enough, they flirt all the time..well she doesnt right infront of me, she does it on purpose! I know she does! I ignore it. That's what I do, I pretend I don't care, because I dont want to let them see that I'm weak. And while that happens I don't speak to my boyfriend, I don't say that I'm mad, but it shows, because it ticks me off. How he can even do that right infront of my eyes, it hurts...
After I found out that were talking smack, we broke up. My ex and his 'good friend' told the whole school I'm a jealous B*tch who uses people and is fake. Sure I cried, because it bothered me, I'm not that type of person and I know it, it hurts cause then people mistake me for a rumour...a pure rumour.
I never told the whole school or even anyone besides my best friends of her talking smack and being dirty dirty with my boyfriend (well not doing dirty stuff, but talking dirty - but I mean, does she have no respect for herself? Like how can she turn a girl, such a pure and precious gender into one of those horny dirty males? How?); But yea, she told all the grade 8's that I'm a slut when thats not even close. She turns half the grade 8's against me. But you know what? a lot of them came back, they told me what she said, Sure I got pissed but I never said anything out about her, and I knwo so much. It's because I don't want to sink that low. Now, the half that hated me are good with me, they tell me why I don't say anything about her, I shrug my shoulders.

I've learned that I don't want to get involved with anything, I just want to do my part. She can say whatever she wants about me, because as long as I know who I am, I don't need ot listen to invisible people like her. Sure, I've thought about saying stuff about her to everyone, and those things could surely turn even my ex against her, and her best friends against her, but I didn't. I highly believe in Karma, What she does, goes back her way. I still hold a grudge against her, but I have the right to, I don't need to forgive her if I dont want to. So I totally understand why you want to let it all out, and it helps! ^.^ Now I live much happiliar, sure I still love my ex, but I keep it inside. Noone needs ot know but me and my friends!

But to this day, I still wonder, How come he told me he loved me the most and can betray me for a friend thats a GIRL, I mean, I was his girlfriend, not her! It's suppose to be me. Whatever I did, I would always think of HIM first! But It really hurts to know that I'm not evne placed second in his heart...because first will always be his friends..but second...will be that girl...the girl that put so much pain and pressure on me that I was afraid to walk through the classroom door to see all the stares...but now I don't care.

I really hope my personal experience can answer even one of your questions. ^.^