My Girlfriend wants to break up with me because she can't get over the fact I've slept with other people?

How can I prevent it ending over something I have no control over!? She resents that I had a past life, where admittedly I slept around with any woman I could just for kicks and for self esteem. I changed. Meeting her and starting to go out with her was the point where I realised that I didn't need to do that, that I could just be happy with who I was. I focused my energy on work and her. However the problems I had caused myself with my past caught up with me, and I recently found out I had failed my second consecutive year of university. In particular she resents that I had sex with an aquatence of hers who is especially undesirable, and she knows intimate details of the encounter. She uses this information to ask me hurtful questions about the incident, and uses it as ammuntion as to hate me. Numerous people I've asked have pointed out she's being immature, but she's only 18 (i'm 21), she has fair reason to be angry. She frequently felt very upset over the summer so far being that we were unable to see each other much due to her restrictive family. She is currently holidaying in spain, and upset turned to hate as she told me that she'd been thinking and all she could think about is me and other girls in the past. She now hates who I used to be, and professes that I couldn't change. I have changed, my loving caring treatment of her shows that. Please can anyone help me or give advice!?

I think you GF has some issues and needs help. If she knows these things were done before you started going out with eachother she has no room to use it against you. Her insecurities about your past are hers. I would urge her to have some counciling if she will. You cannot be held to ransom for things you did before her! It may be in your interest to let her go as hard as it seems. Why should you be punished for living a life before her? Good luck

Right for starters she has NO reason to be angry. i think if she doesnt like it then she should jog right on, what does she want you to do? change your past. At the end of the day people CAN change, and if she doesnt believe you could off then why is she in this relationship? just sit her down explain to her yet again that youve changed and if she doesnt believe you then tell her to piss off cos WOW you had a life before her, she didnt even have to know about that, its none of her business, she should count herself lucky that she even knows about your past.. sorry for rambling! had a few off these "past haters" before.