My policy as of late has been:
When making a decision in the present, I have been taking anything other than a full yes to mean no. It sounds like he might not be totally with it. Ultimately, it is your choice but he seems to be acting a bit fickle. He should be able to express if he is or is not okay with something when you ask for his opinion. He may be uncertain or testing you or witholding...? There's a difference between discreet poly and messing with your partners head. Giving you conflicting answers would seem like the latter to me. It's not that you need his permission but as your partner he should be able to share his needs with you. You can decide if his needs are something you can meet. He can decide if he can give you what you need to.