As you said, because it may affect how you feel about opening up with your therapist, it is your business. You don't need to be nosy, just say you read some things and would like to hear her point of view. After all, we should never go by hearsay, and there are two sides to every story. I don't think it would be out of line to ask about the situation. The worst that could happen is she tells you she is not at liberty to discuss that information.