Remember, he is not your partner or your friend, he is just there. You do not have to let him under your skin. Turn down the gain on your butthead antenna. Visualize a force field around you off which his assininity just bounces. That is how most people (including my best friends) deal with me: they just do not listen to me.
This is an incredible growth opportunity for you. Seize it! You will tolerate us idiots more effectively for the rest of your life.