When your friends discover that your history has been less than desirable. They're unbelief in the story of your ugly life is the proof that you have made the right and correct decisions in your life.
Just smile and express gratitude.
Re-assure them that it is OK. Because some who may hear may not be able to handle with this new information about your past. You may have to help them through with the living with those old memories of yours. Keeping your history of abuse, torture and abandonment a secret may be a wise thing to keep in order to protect the innocent from re-living your life.