If you get their permission, you should not tell anybody unless you have reached the point where you are not defensive about your child's homosexuality. Unless you can be positive about your own feelings more than likely you will communicate your unhappiness or doubt to others. It is very helpful that you talk with people outside your situation. The knowledge that there are other parents who have gone through very similar situations such as yours helps you to realize that you are not alone, and provides you with sympathetic people who can help you to clarify your thoughts and feelings. Therefore, when you are ready to share your feelings with someone outside of your family.
Resolution takes time.
You will evolve as a wiser parent with some very valuable parenting skills. My child is gay.