In The Great Gatsby, thus pens Fitzgerald:
‘However—I want to see you.’
‘I want to see you too.’
‘Suppose I don’t go to Southampton, and come into town this afternoon?’
‘No—I don’t think this afternoon.’
‘It’s impossible this afternoon. Various ...‘
We talked like that for a while and then abruptly we weren’t talking any longer. I don’t know which of us hung up with a sharp click but I know I didn’t care. I couldn’t have talked to her across a tea-table that day if I never talked to her again in this world.
It's a conversation between the narrator, Nick, and his quasi-partner, Jordan, followed by Nick's commentary.
I'm struggling to interpret the conditional sentence. Does it mean,
I couldn't have talked to her that afternoon, even if it meant I would never see her again.
Even if this had been my last chance to talk to her, I couldn't have done it.
Or something else?
More elaboration on the possible dialect or register that would featur such a structure is appreciated.