My response to the writer:
I admire your courage and strength. You have survived great emotional trauma and made a life for yourself. You are healthy enough to both recognize conflicted feelings about some of the most complex issues a person can face and to express them clearly and honestly. Whatever more you do, and wherever you go from here, I want you to know that I feel honored to address you because of the specialness of your accomplishments, and what you have to offer the community and the world with your wisdom.
I have been faced with similar questions plaguing others. I too am a survivor of abuse by my Rebbe, which poses a different set of questions and emotional conflicts, but I know many other people who have survived incest.
The reason that contacting law enforcement is almost always a good idea is for safety. In the case you quote of the author whose problems changed when police were brought in to stop her from being abused in her family, experiencing incest on an ongoing basis creates such a high level of risk for damaging one's life, that no serious consideration can be given to "collateral damage" that occurs when stopping the abuse. This is the halacha, and the law in most civilized countries, and while not necessarily true 100% of the time, from a clinical perspective the vast majority of the time the "new" problems are not as permanently scarring and damaging as child sexual abuse allowed to continue.
As for contact with family, each survivor needs to work this out for themselves. It sounds like you have a conflict about wanting to stop the charade which feels soul-killing on the one hand, but wanting to keep it up for the outside world so that you will not have to lose communal status on the other. This situation presents you with little alternative but to make the choice you have made: to cut off ties to your family. What if you were to break the charade ONLY inside the family? What if you confronted all the members and tell them how you feel? That you can understand why showing a united and positive front to the outside has benefits, but at least internally can everyone acknowledge that there has been grave sinning and abuse that has gone on, and can they not only validate you, but work with you to hold your father accountable, and make him do Teshuva? You might be able to have your cake and eat it to. You could get healing support and validation from your family members, thereby allowing you to have contact with them without feeling "killed", while at the same time you would give up the validation of your story by the whole world, by choosing to keep the healing process within the family. Another advantage of confrontation vs. total distance, is that it is another step towards making others safe from your father. Do you never worry about your nieces and nephews? Since your father has admitted his behavior, there is some reason to hope that others will support you, because they will not be able to deny it happened, which is usually the way family members choose to avoid having to deal with the problem.
What I am suggesting is just that, a suggestion. It is not intended to state "the right thing to do". Each situation is different, and there is no one size fits all right or wrong answer when it comes to healing.
Good luck, and Hashem should continue to give you strength in your healing,
If there were another way to stop the abuse without the police, such as removing the children from the home, that might be preferable in some cases, but that does not always stop the abuse. As long as the molester still is allowed contact with the child, there is risk of continued abuse, and unless you involve the courts, it is impossible to guarantee that such access will be denied.
Another reason to involve the police is to protect other people. While many children do survive and some even go on to thrive after sexual abuse, removing the child from the home does not stop the abuser from molesting other children. The only way to provide serious protection for all children from an identified child molester is to have the molester confronted and held accountable in a court of law. This would not only help the child who is being molested be protected, other children the molester may have access to be protected, but it would also create a situation in which the molester can be helped to stop his criminal behavior and live a more healthy life. The victims need therapy, but the molesters need to be helped as well, and for them, treatment is usually only even somewhat effective if it is court mandated and monitored.