Most Helpful Girl
When she is older she will no longer be beautiful and then she will realize that she is no longer valuable to men. You have your education and your intelligence and that is permanent - nobody can take that away from you - so be happy and use your intellect and education and get another girl and marry her BEFORE you have sex. And get her pregnant. Then you don't have to worry about her leaving you.
Most Helpful Guy
You got used. She was most likely banging so you could keep educating her so she could land a job. And she was having sex with your best friend for love and affection. She is in asshole. You just have to heal and move on. It will take time to heal from a long-term relationship. Spend time with friends and family. Lose her number.