I don't think you should have a Big Conversation on the phone. But I think you should get this across on the phone or in an email: I know that "anything I say [at this point] will just be empty words unless I can back it up with actions."
I don't know why you're trying not to show that his words and actions really got to you. "Trying not to show it too much, as I know that's not the kind of person I want to show him."
It seems to me that that's precisely the "kind of person" you want to show to him, namely, YOURSELF, one who has feelings, who is touched by his words, who doesn't want to lose him, who wants to change the past, who loves him, etc.
What does this look like to you: he drops a bomb and you keep a cheerful face on everything.
Unless I'm misunderstanding, that might get you the label "ice princess."
