Changed your mind my friend?

Need help..so confused, don't know what to think? Me and my ex -girlfriend where friends. We have been friends before we got together and when we broke up we stayed as friends. We broke up like 2 to 3 months ago. During the past we have broken up and gotten back together, some of those times I would tell her, that we shouldn't be friends so I can move on. But she would get pissed off because I would be braking my promise (to stay as friend no matter what happened) I made this promise the time we got together and that I was acting like a child and I have kept that promise. I have stayed as her friend while she would be in relationship and I stayed single. Now she is in a relationship and seems to love the guy a lot, and as her friend I would give her support when they get into argument, be the shoulder she can cry on and give her some input on how a mans mind work. She was cool with me being her friend, until of lately. I told her that I liked someone, now she don't want to be friends with me anymore. She don't even want to have a history with me anymore. She want everything as if I never knew her? Why? I know that being friends with your ex can cause issues, but why now? I am so confused.Changed your mind my friend?Because she still has feelings for you. She doesn't like knowing that you're going out with another girl. It hurts her.