I met a girl last year. We became good friends. Then she started to take interest in me. I also started liking her. We were in relationship for almost 2 Months. But after that, things began to change. She told that we should remain best friends. She said -"we are from different backgrounds. Our families won't agree to our marriage". But I insisted to be in a relationship. After 20 Days, she told me that she had a relationship with a boy since her 12th standard. They had done their breakup 1 Year ago. But still she loves him. She tried to forget him ,but she failed. She said that she is unable to forget him. So she thought that she might be doing wrong with me.And she said that she doesn't want to play with my feelings. She wanted me as her best friend. I gave her the emotional support she wanted. I thought that she would forget him one day. But nothing happened. After 7 Months she asked me," Can I go back to him?" she was very unhappy without him. So i told her to go and patch up. Now both of them are together again. But i love her a lot. She cares a lot for me. She considers me as her best friend. She doesn't want me to go away from her life. She requests me to stay in her life as her best friend. But i can't bear the pain of my heart. Its unbearable. I can't see her with someone else. What should I do?