If a friend were to tell you the poignant story that you relate I doubt that you would tell them that there ought to be no end to their guilt, that getting spooked by marriage and backing out is a sin that can never be forgiven. Think of yourself as a friend. You apologized many times. You have suffered.You did not by any means destroy your former fiance. Truly, it would be irrational to keep torturing yourself and if it is irrational no amount of reason is going to assuage the guilt. Perhaps though it isn't all guilt. Emotions are not as easy to individuate as things in the world. Perhaps there is a strong admixture of regret for not being with her, of missing her and feeling alone, maybe that is what you need to deal with the most and that could be very hard and painful. I hope very much that you get your soul back- it sure sounds as though you have a lot of it.