Is this wrong of me to do? Am I a bad person for asking this?

My girlfriend who I have been with for a year and 2 months now, who I love very much and would do anything for if she just asked is doing something I don't think is right. We had alot of problems with her ex boyfriend who lived in another state at the beginning of our relationship. Nothing too bad just a little texting and talking behind my back. Well it ended but needless to say I hate her ex and everything that has anything to do with him. She was still friends with his sister. No biggy. Well a few months ago him and his sister were in town. She wanted to go see his sister so badly and hang out with her even if it meant being around her ex. Well I hated this and we fought about whether she should be able to spend time with her or not. Eventually she had her way and had her spend the night at my girlfriends house a few times. Well around this time, by my girlfriends request, I started texting her friend, nothing big, just to get to know her so maybe I could get past who her brother was. Well on one of the days she was hanging out with my girlfriend they decided to come over to my house. Her friend and I had gotten to know each other and had started to become friends. Well before I was even with my girlfriend when she was with her brother, my girlfriend had a crush on his sister! Well apparently this was still happening. Even more strangely her friend also liked me. Ill admit I sort of liked her too, but nothing that would threaten our relationship. Talk began of a . My girlfriend was totally into the idea, so was she. So we all three started trying things with each other. Nothing too ual just a little experimenting. Anyway after this happened her friend really started liking me. But my girlfriend also realized the whole thing was not what she wanted at all and regretted the whole situation. After she left town she was talking to me behind my girlfriends back. I eventually put a stop to it because i didn't want problems caused in my relationship. Well its a few months later now and things aren't very good. She is still texting her and still talking to her. She knows how much I love her and what i would do for her... It's like she just doesn't care. I ask her to stop. I beg her. I tell her it hurts me that she is still in contact with her. She just doesn't care. She tells me i'm being controlling. Tells me I'm the bad guy in the relationship. She knows i hate her texting and talking to her but she does it anyway. She tells her things about us. She deletes her texts. I ask her to stop.. I have so many times... Its always the same. Im wrong, shes right. It's wrong for me to try to get her to stop talking to her friend. I'm wrong. I tell her i can't stay with her knowing that shes texting her and talking to her as much as she is, knowing how i feel and how it hurts me. She doesn't care. She says she loves me. But then tells me just as easily that she is going to get her friend out of her life. We have fought over this so many times. Now she is telling me, let me talk to her or get out my life. Just like that. I feel like she doesn't even care about me. She says she still loves me and cant understand how i feel like this. Just earlier she texted me **** you im about to ****** dump you... all because i was trying to get her to understand how neglected and **** i on feel.... She doesn't care... And even through all this... She still claims to love me. She still claims shes right and i'm wrong. I'm not trying to be controlling its just so wrong of her to do this. My gf made her friend hate me. Im not allowed to talk to her. Im not allowed to text her. But my girlfriend is. And she is gonna break us up just to get her way. Also what she always uses to reinforce her story and her reasons, is a few times in the past when we have argued and things got way out of hand and I mistreated her. Its not happening anymore but she cant let go she blames it on that. I love her so much.... Is it so wrong for me to ask her to stop texting or talking to her friend? Is it so wrong just for me to ask for her to do it less? Please someone help me...