Why? There are other EU nations which haven't joined the Euro. It might be likely that the UK has to give some ground but not all of it. We might join Schengen, for example (and about time too).
I cannot see any way at all that May gets her deal through, frankly. Once that's happened is when the really interesting stuff happens.
Can see a second referendum based on Remain vs No Deal. I'd expect Remain to win that, but it's by no way certain.