A brief snippet from Myss about the saboteur:
This may be the most difficult of all the archetypes to understand, because its name is associated with betrayal. Yet the purpose of this archetype is not to sabotage you, but to help you learn the many ways in which you undermine yourself. How often do you set new plans in motion, only to end up standing in your own way because of the fears that undermine those optimistic plans. Or you begin a new relationship and then destroy it because you begin to imagine a painful outcome. You begin a working relationship with another person and find yourself once again in a power struggle that could be settled peacefully -- but you fall into the same destructive pattern because you fear the other person.
The Saboteur's fears and issues are all related to low self-esteem that causes you to make choices that block your own empowerment and success. As with the Victim and Prostitute, you need to face this powerful archetype that we all possess and make it an ally. When you do, you will find that it calls your attention to situations in which you are in danger of being sabotaged, or of sabotaging yourself. Once you are comfortable with the Saboteur, you learn to hear and heed these warnings, saving yourself untold grief from making the same mistakes over and over. Ignore it, and the shadow Saboteur will manifest in the form of self-destructive behavior or the desire to undermine others.
To learn how to become aware of the action of the Saboteur within, ask yourself these questions:
What fears have the most authority over me? List three.
What happens when a fear overtakes me? Does it make me silent?
Do I allow people to speak for me?
Do I agree to some things out of fear that I otherwise would not agree to?
Have I let creative opportunities pass me by?
How conscious am I in the moment that I am sabotaging myself?
Am I able to recognize the Saboteur in others?
Would I be able to offer others advice about how to challenge one's Saboteur? If so, what would it be?