I feel that the decision hasn't really been made until the act is finally committed. Before then, one's mood may change to follow a different path. Maybe some people (maybe you?) just reach a point where they are certain beyond any doubt that they will go ahead with it, but personally I recognise in myself an uncertainty beyond my control, that may cause me to withdraw at any point. However, I have felt a definite kind of relief in realising that ctb is not immoral or shameful.