answer:You teach people how to treat you. In the past you probably gave him the idea that he can treat you as such. The best way to approach the resetting of boundaries is to talk to him reasonably, with little emotion, and with a direct statement of how you feel. Maybe something like: I know that sometimes I am willing to go along with your ideas and suggestions, but not all the time. I do not appreciate you getting defensive and angry when I say no to you. Sometimes I just do not want to do, or agree with, what you want/say. If this continues, I will not continue to be your friend. (Just a template, you get the drift.) Of course you have to mean it, and be willing to accept the consequences of your action. If you are at your wits end, and he does not react favorably to your boundaries, then maybe he is not the right friend for you.