The EEC was founded originally to ensure co-operation between the 3 big western European countries (France/Germany/Italy) and to reduce the likelihood of armed conflict between them. The UK was not wanted originally as a partner, and after the 2nd refusal to admit it in the late 1960s and with the benefit of the retrospectoscope, should have accepted that decision and moved on. When the UK finally joined, it was as a lesser partner and the big 3 remained the same until German unification. Subsequent to this event, Germany has become the dominant partner, due to its size and economic power.
Some might view the Greater Germany of WW2 as a forerunner of the EU in some ways, although it was clearly not a voluntary partnership. Napoleon's Continental System, established following the Berlin decree of 1806, was another autocratic attempt to create a European continental block opposed to the UK.
One thing that has become clear over the last few months as Brexit has evolved, as illustrated by the spat over vaccine availability, is that a divorce is rarely amicable.