My life duo and I have both been playing since early season 2 as well, so we understand the frustration of dealing with each other being stubborn about thinking that we know what we're doing, and raging at each other about keeping each other in check. It's pretty funny when we talk about it, but we're getting better at giving more constructive feedback. Sometimes what it takes is for someone else telling us, "Hey, that's not working," before we understand that it's not just our pigheaded partner being an all-knowing ass.
Anyway, you have two choices. Find a constructive way to tell him that it's not working or have someone else observe him and do it. If those don't work, your other two choices are to suck it up and deal with it or stop playing with him until he gets the hint that he's really not that fun to be around.