because he loved me

When I was 12 years old, there is a guy who falls in love with me. he was 15 years old that time. First I knew him from my bestfriend, she fell in love with that guy, and she often shared stories about him to me. They often communicated via cell phone. One day on her birthday, she wanted me to ask him for his picture. I found that guy and immediately asked him his picture and he said "if you want my picture, we'd better take a picture" and I said "No,I don't want. that photo isn't for me but for my bestfriend" and he immediately gave me his photo. After that moment, he started to care at me, he liked to ask me about my situation. One day I knew him well, he asked me "do you want to be my girlfriend?" I said "I'm not allowed to have a boyfriend" he said "okay". But he still cared with me, and I began fall in love with him. One day I heard that he had a girlfriend, and that day he didn't care with me anymore. I cried for no reason. I really hoped he would love me again. I intend to forget all about him. After  nearly a year  I could forget about him and those memories, even though not all of them. Suddenly, one day he began to care at me again and I was very happy, he said he has been broken up with his girlfriend but the next day I heard that he made his relationship backed with his girlfriend. I cried, I couldn't explain my feelings using words. I though "so i'm just be your impingement?" I was desperate at that time. And from that moment I didn't want to love someone else.