They say if you love someone let them go and if they come back to you then you will know, that they feel the same way and this time its real and you have something for which most people would kill.
I know its hard but sometimes it must be, that you have to leave it to fate to find out if it's destiny. They had their doubts but you gave them a chance, to experience the world and still they came back. So if you want it you know this relationship can last, if you work for a future and don't dwell on the past.
So let your love go, let the bird fly. For when it returns it wil be with a love that wont die.