A little different perspective. Reading between the lines I appears you are a very competent rider yourself. Perhaps he gets nervous that in traffic and tight situations he is tense because you might do things differently and that causes him stress? My wife and I are both very experienced riders and she is a capable captain when she rides with others and a great stoker but we sometimes "disagree" on the best lines or gear choice etc. I don't stress any longer about it and we just agree to disagree at times but it could be an issue if I let it.