Feeling of Being Cheated

I met a girl 2 months bak. we were becoming real good friends and then best friends...then one day she tells me that she likes me....so I said why dont we hang out...so she said ok but discreetly...I was kinda wierded out...but i understood...

after two days she tells me that she has been going out with this other SOB..for 3 years...and she wants a break in that relationship but didnt want to break up wit him....So I said "so I''m the looser who had to come by is it?..Then she says NO and that she loves me....mind you we never kissed yet...so i told her we will be best friends nothing more....but things were getting even more tensed around her,..there are times sometimes we go over the boundaries....accidentally...but eventually the next day I start regretting the whole thing....5 days back She kissed me on the lips and...I was pissed I told her about the principal I told earlier that I would only have my first kiss with a girl who is MY GF....not Best friend....so after that the next day she goes to hang out with her Boy friend and i begged and pleaded with her not to kiss him please be with me...and she did say that she was better off with me...that whole day when she was hanging out with him...my mind was in such pain just thinking she would be doing all that stuff she did to me TO HIM...and that just killed me...next day I told her to decide since this is getting too hard...and she says she loves him and loves me as a Best friend...so told her to go screw herself...

I helped through her A/L exams where she had undergone sooo much mental torture with the boy friend and all...I also helped her prepare for uni interviews...and the list goes on...I even composed a music for her....Once all that is done...she sends me on my way saying Thanks for being there for me...really appreciate it...Bye....

i was badly hurt about this.....But nowadays I miss her badly coz we used to talk on the phone for hours and hours...

Please guys give any advice...that I can use...I really need to get over this