I understand you have boundaries but that hand wave is rude (OK, probably true, I did do a dismissive wave with my hand in the air). Then he said you're making the choice to throw away all those other things. That is on you. I said, F you, H. and walked away. He then left to go help a friend move.
Guess saying F you and walking away isn't really DB-ing. I very much feel like it is my own business how friendly I choose to be with him after we split and I refuse to be his crutch for not making a decision. Yet in those moments I'm kind of stuck still-- I don't have a good answer that isn't either controlling or a lie. Is it just a calm "I understand you see it that way" and disengaging?
May, I see nothing to fault in these actions. He said, "I understand you have boundaries"--then why did he step on them again?! You seem to have been consistent about not being open to discussing OW, helping him make his decision of you vs OW, or his fantasy of You + OW. A rude boundary violation earned a hand wave plus you walking away. A rude second boundary violation earned an F You plus you walking away. You're teaching him you respect your boundaries. You don't owe him listening to those topics.