The reason for the division is that no party has had a workable majority since the referendum. Combine that with the fact that our contrarian politics means the opposition would not back any deal brought to Parliament simply because it was negotiated by their opposition and it means perpetual log-jam.
Logically extracting ourselves from the EU was going to be a transitional process taking c. 15 years and the way to do this would be to become Norway, then Switzerland, then Canada whilst being able to negotiate without the time and political pressures we're currently seeing. Naturally if 5 years into the extraction process a new government were elected with a manifesto against further extraction or in fact for re-integration, then we'd do so. If a government was elected on further extraction then we'd continue on that path.
This is the same as all laws of course, you end up with successful parties being right in the centre of the populaces belief systems. Taxation as an example has been similar (as a % of GDP) under all successful governments of the last 20-25 years; meaning we have population consensus on this. Political maneuvering and population consensus would naturally result in all parties after a few elections being comfortable with the status quo on Brexit (whether that be sticking with Norway, Switzerland or Canada would depend on negotiations by the party or parties in power).
That's why Johnson's agreement to have further discussions seems fine to me (as did May's). If Labour win an election they can negotiate the next phase as they choose, if that's further integration then that would be their prerogative. If the Brexit Party won the next election then they would torpedo discussions in favour of the WTO. If the Tories won they would continue on the current path.