I have to say i'm sorry. You can't. Physically way, you can't. Even she truly love you back then but after the break up, things changed. She might meet someone new, have new mindset about love, changing environment around her,... This is not related to the spirit you dealing with.

This thing.. If its a spirit.. Let me explains it to you.

She can try to break your connection by: make your ex feels negative, make you seems.. Ugly (yes, thats right they can, like you thing a watch is ugly but someone else will love them. Simply changing the way others look at you.), and in the right time will give her a small push so she will sure breaking up with you is right.

But they can't really change her all. Just a little push time by time. Will lead to a different result. Little hard to explain.