I think setting some guidelines about open and honest communication is perfectly reasonable. It's like asking that he gets informed consent both from his date and from you before anything procedes beyond friendship.
I have some other concerns in your situation though, it sounds to me like whatever he says goes. You've said that you would like a boyfriend and that he isn't ok with that so you won't go there and you've also said that you would perfer that he meet someone new rather than persuing somthing with someone who he already knows. Poly shouldn't be one person compromizing all the time. Either you both have the freedom to persue whomever you chose or both of you are considering each other in your limitations. Just my 2 cents worth, feel free to disregard it.
Everything will be ok in the end. If it's not ok it's not the end.