This healing is accomplished by finding compassion for yourself. You have to go back when you let yourself, your children, or the people you care about down. You need to understand why you made that choice. Regardless of the outcome, what was your intent? Were you trying to save your marriage or protect your family the best way you knew how? Did you not want to hurt someone's feelings? Were you not able to see other possibilities?
You did not have the awareness and understanding of the effect those choices would have at the time. If you did, you would likely have made different choices. Hind-sight is 20/20. It is brutal to yourself to judge what you did in the past based on the awareness that you have now. Give it a rest.
So... find some compassion for that person that you were at the time. You were just trying to make it through life the best you could. You acted based on the information you had, and the possibilities you were able to see at the time. As misguided as it may now seem, you likely did the best you were able to do at the time.
The resolution (and healing) is to forgive yourself for what you did and... to promise yourself to never to that to yourself again.