It sounds like this relationship is very intense and there is this sexual heat. Keep in mind that relationships can have gret potential and still not happen. Sometimes relationships fail simply because of timing. One is with someone else and the other isn't. She has to be open to a relationship with you. She obviously has feelings for you but she has to have the perspective that she is open to a good guy. She brought this guy back knowing that you would be in contact. It may not be that she doesn't love you but more so that she hooks up with guys that aren't good for her. This is a huge problem because she will always make herself available to these guys that treat her horrible. She has to want a healthy relationship.
She knows you like her so can stay close for now and hope that she wants someone her treats her well. You don't have to tell her ; she already knows. She has to want to be treated well. It's up to you whether you want to wait.
Please press accept; this is the only way I am compensated
I would try to contact her once and let her know you are sorry and that you won't contact her until she contacts you first. Give her space after this so that she has time to embrace your apology. Don't worry for now. You have waited a long time. If it's meant to be she will let you know that you are forgiven.
Be back later