My situation is more complicated than I thought, can anyone help?

Hello all, first of all recommend you read my first post to understand the situation, however I have been given a more clear picture of what had been going on since the break up and possibly the real reason why. I found out from a friend that she may have cheated, now I knew there was a possibility since I heard just after the break up she may have kissed another, but I denied it, but since she contacted last Wednesday I decided to speak to a friend about it, and that when found that the cheated may have been more true than false, as a week before we broke up apparently she was eyeing another man, it confirmed my fears and my friend did why would you get back with her, and I said “Like I said, I was under stress, I’d had been lied to by family, they told me that the living circumstances would be temporary and I would come home, so you can imagine how I felt, plus being away from Em tore me apart, it still does, I hope I wasn’t controlling, if was then I’m sorry about that, I feel like she is my soul mate you know, that my actions and behaviour were do to stress, but now, I am strong again to the most part, I really need to tell her this, I mean after all that happened with Dan, I just knew I was meant to be there for her, to comfort her, being far away takes that away, I hope she can one day feel that she can invest in what we have and I hope she can give our love just one more chance, is that too much to ask?” This was my exact message to friend. I do love her, and I can forgive her, as far as I know she broke up with the guy she was with after me not long ago, so what do I do? I thought of writing a letter to her, because that can’t be ignored, so I hope to all who read this will share your thoughts and to give advice on what steps I should take.