That's just childish and even foolish if you ask me. Not being open to criticism surely isn't the right attitude to run a company. Hell yeah he can blow it back in your face but what needs to be said needs to be said! If he can't appreciate some input/comments well than I guess that's his problem and he'll probaly regret in the future.
Do your thing! Try not to get all to emotional and make clear he shouldn't take it personal. Wouldn't recommend supplements either but if you really suffer from anxiety around this Propranol might be of some help... But than again just do it, it seems the right thing to do
Spoken like a true businessman. I absolutely love criticism, either because I take pleasure in 'returning it to sender' when it's unfounded criticism, and it's also a great way to gauge a perspective that's not of your own.
I used to have these 'confidence' issues as well, they're extremely hard to overcome. You need to be a diplomat if you're going to talk to your boss and you need to say something important. Remember, it's not really what you say, but how you say it. You should read a few quick notes on reading body language and tone, etc... It might calm you down. Just remember, be positive, seem absolute with your suggestions, and always suggest your ideas 'in the best interest of the company'. If your boss sees that you genuinely want to improve his company with your suggestions, he might get comfortable with it and will flow.
If he takes it the wrong way and acts childish, well take consolation in the fact that you're working for an immature employer, and being the potential seeker that you are, you owe it to yourself to find better opportunities.
Be honest, talk firmly, and tell him what's on your mind in a positive manner.