It is difficult to answer this question without knowing what you discovered on the Internet about your therapist. Did you find out that he was convicted of molesting children? Did you learn that he robbed a bank or took part in an adult film or did he get caught selling drugs to children, etc? If he were guilty of any of the above I might be able to understand why you have lost your faith in him but without knowing what he did that you find so reprehensible and shameful, it is difficult to advise you. I can only offer general advice.
If you feel that you cannot go on with your therapy sessions because what you learned about him is unbearable, then it would be wise to find another therapist. Only you know how you feel about the information you have learned and how it makes you feel. This means that only you know whether you can continue with therapy in light of your discovery. If what you learned bothers you and you can’t move past it, then it may be time to find a new therapist. You also have to consider the fact that what you have found may not be a “real” reason to discontinue therapy. In other words: this may be a problem that needs to be worked out with a therapist. Are your feelings towards your therapist appropriate? Are they reasonable and accurate? I know that they bother you but should they?
If you would like a more detailed and specific response, consider writing back and providing more detail. For instance, it would be informative to know what information you learned about him, an explanation about why what you learned bothers you and why you said that “I’m starting to wonder if his own shame about his past is preventing him from fostering an open discussion about how I feel.” If you provide more information, I may be able to give you more than a general answer. Thanks for writing.