I still love her a lot, how can I get her back?

hello, I was 20 years old and my ex-girlfriend was 19. We got in a relationship which lasted for 9 months. She broke up with me several times for stupid reasons but I always found a way of getting back together. Our relationship was perfect and we loved each other so much. The fact is she loved me more than I did. After 9 months, due to numerals fights, I decided to end our relationship. She cried a lot and all I did was to go out with my friends tried to talk to me but I had no feelings for her left in me at that time. She was so hurt, after 5 months I realised the big mistake I had made I went to her, we talked. I told her how much I loved her and this won’t happen again. She cried and was angry at me but got back together, our relationship was stronger than before. I was more caring than before but again unconfident than before. I limited her from meeting other boys. I don’t know what happened but after 3 months she broke up with me. I wasn’t that much hurt and I didn’t try much to win her back. Within 3 weeks she had a new boyfriend. I saw a picture on her on facebook with her new boyfriend which broke me into pieces. I found out that she had been in a relationship with him ever since we broke up. I was unhappy. I was quiet about everything. I couldn’t even to talk to my friends. I texted her and told her I was in depression. She asked how she could be a help to me. I apologized to her for not being a good boyfriend and asked her to come to me, she said it was too late she has a new boyfriend now. I’ve been texting her, all she does is to ask me to move on. I cannot move on. I love her a lot, how can I get her back?