Brexit and Northern Ireland

Yesterday's collapse in Brussells really makes me wonder whether Brexit can go ahead.  Rather than a minor miscommunication over the exact text, it seems to me to be a far more fundamental failure with the failure of those demanding Brexit to understand the nature of our relationship with the European Union, and indeed the nature of their own demands.

Given the huge cost of a hard border with the Republic to Northern Ireland, and the risk to the Good Friday Agreement, I assume that the DUP genuinely wants an open border, but I don't see how you can have that with Northern Ireland remaining in the Single Market.  Leaving the rest of the UK outside the Single Market would then create a hard internal border between Northern Ireland and the rest of the UK, which would obviously be anathema to any unionist. 

The whole mess has also led to exceptionalist demands by Scotland, Wales and London for a similar bespoke deal, which would create even more internal border issues, quite bizarre ones in the case of London. 

Keeping the whole of the UK in the Single Market is hated by the hard Right as the Conservative Party is hated because it would be incompatible with their zero regulation fantasies and tantamount to remaining in the European Union.

I really can't imagine how the Brexiteers are going to escape their inherent contradictions on this one.