Brexit is a divorce and it's a highly unusual divorce that doesn't destroy someone's life. What a mess.
The problem now, though, is that it's the proverbial Gordian Knot ... which was a legendary knot for a reason ... it couldn't be untied. Alexander The Great solved the problem with his sword.
I have to admit, I was always skeptical about whether the EU could work. The "United States of Europe" implies the dynamics of a "country." But the EU is not a country, it's a "something else." Some things in life require absolutism ... like pregnancy ... either you are, or you aren't. Either you're a country, or you aren't. And if you aren't, then what are you? The EU's more than a trade pact (like NAFTA), more than an alliance (like NATO) and more than a membership in an international organization (like the UN).
Sovereign democracies subjecting their sovereignty to an un-sovereign bureaucracy in, arguably, the most convoluted electoral system ever devised by Man. What is THAT? And that's just the Parliament ... none of the other EU organizations with which it shares power are elected at all.
https://en.wikipedia.org/wiki/Elections_to_the_European_Parliament
I suspect Brexit will happen, deal or no deal, because there are already too many cats out of the bag. Animosities already run too deep. It would be like reconciliation after adultery ... much easier said than done. Trust is a delicate thing. My question is whether the EU itself will survive once the UK exits. All organizations require that its members display a certain degree of inexplicable "stick-with-it-ness." Married people stay married, in no small part, because they like the idea of "being married" more than the idea of "being single." Relationships possess an emergent property.
Brexit sets a precedent and precedents can become cudgels to endlessly coerce others into giving you what you want. "Give us what we want or we'll exit too." When Trump won the election, a bunch of crybabies in California started a petition for secession. "Since the rest of the country thinks we're just a bunch of lefty lunatics (which is true) ... we'll just leave."
One of the gnarliest issues I see is that of "wealth transfer." Inevitably, in large countries like the US or Canada, certain parts of the country are wealthier than others. Natural resources, geographic advantages, capital concentrations, etc. make equalizing economic opportunity impossible. And so, the rich parts end up subsidizing the poorer ones. In Canada, provinces are even referred to as "Haves" and Have-Nots." It's politically controversial but, inevitably, that's what countries do. The binding forces of nationalism outweigh the allegation that the poorer parts are creating their own problems. Because there's a single political mechanism though, the richer parts can force changes in the poorer parts to try to, at least, minimize the disparity and hence the conflicts.
There is a similar phenomenon happening in the EU. Germany vs. Greece at the extremity but also the North vs the South and the West vs the East. And, it's not just economics either. The Poles have a decidedly different opinion about the threat posed by Russia than do the Italians. And Hungarians have a much different idea about how to deal with the millions of illegal migrants than do the French.
In any relationship, you need to have a bit of "Opposites Attract" (so it doesn't get too boring) and a lot of "Birds of a Feather" so that commonality of interests create bonds that bind. In the EU, I think the realities are reversed.
Quill
Elections to the European Parliament
Elections to the European Parliament take place every five years by universal adult suffrage. 751 MEPs are elected to the European Parliament, which has been directly elected since 1979. No other EU institution is directly elected, with the Council of the European Union and the European Council being only indirectly legitimated through national elections. While Europarties have the right to campaign EU-wide for the European elections, campaigns still take place through national election campaigns, advertising national delegates from national parties.