You can not blame yourself for his reaction to the kiss. There was no way you could have known something so simple would have created such a dilemma. When someone looks human and mortal, it can be easy to forget they are not.

That might be for the best. Emotions are...messy and need time and space. Just be careful with how you end your relationship? If he's ever ready to deal with having emotions, he might need you. When I spoke with him he seemed quick to assume things and it wouldn't help if he read your intentions wrong.