I do have a couple of thoughts :
The bigger person is usually the one who remains themself, because of themself.
That is - whatever the other person does, the 'bigger' person stays true to who they are. This can be done by asking:
- 'Do I want to partake in his/her behaviour?', and
-'Who do I want to be?'
Both questions are equally important.
It looks like you have answered 'no!' to the first question, but haven't yet worked out how to distance yourself from the emotions his behaviour evokes. That's okay, you'll learn how to with time, if you keep going down the path you've chosen.
The answer to the second question isn't simply 'not that' (ie 'not his sort of person')...who are you when he pulls this sort of behaviour? The answer may help diminish the emotional turmoil further.