[Teresa Edgerton]

If he's had a lot to do with shaping the manuscript he may have a sense of ownership -- not in the sense of feeling justified in ripping you off, but in the sense that he is no longer as unbiased a reader as he was before. If you've followed many of his suggestions, he is likely (in all sincerity, but not necessarily impartially) to be charmed by those parts. In short, he may have become invested in portions of the manuscript in much the same way you are. (Over many years working with different critique groups, I never heard anyone say, "Oh my gosh, I see now that I gave you very bad advice. I wish you hadn't followed it.")

This is one reason why it's a good idea to join a writers group and have several people critique the entire manuscript as you work on it -- different people will "own" different parts, and can maintain the necessary distance toward all the rest. (Also, you know where they live.)

Again, only you know if his influence over your writing has been such that there is a danger he might have become a fond godfather to the project, instead of the impartial reader he was before.