Maybe invite the guy for a beer, ask him to help you (nicely) understand his point of view, and get back to training?
...I also agree with this approach, talking with the guy 'man to man' outside the dojo over a beer. My guess from what little you've said is that this guy just has no respect for you at all, and this meeting will at least start him thinking that maybe he's made the wrong assumption about you. He might not even be aware that he's been such a jerk toward you, and this will at least bring that to his attention. If he refuses or continues to treat you disrespectfully during/after your talk, then the guy is just an arrogant jerk, and there's nothing you can do about it.
...but where I differ from Ron's opinion is that I would NOT
leave the dojo! Continue to train, just ignore this idiot! And don't 'fight' this guy, that's just plain wrong! [A fight won't decide who is right, it just decides who is stronger!!! ...not very Aiki
...by doing the beer thing, you've done all you can to fix the problem, but sometimes problems just can't be fixed ...and life goes on! ...BUT DON'T QUIT!!!!!