This is the dilemma, I don't think the EU does want the UK to suffer just out of spite, but they can't give them a generous deal considering EU stability.
By the way: Berlin and London Stock Exchange markets want to merge, the UK leaving the EU is more of a problem in that regard http://www.bloomberg.com/news/articles/2016-03-16/lse-agrees... (though they said they want the deal to go along no matter the vote)
[1] Front national (FN) in France, Alternative für Deutschland (AFD) in Germany, Partij voor de Vrijheid (PVV) (Party for Freedom) in Netherlands, nationalist movements in Poland, Hungary, ... Election in Spain might also not turn out to result in a EU-friendly government... (seriously could go on...)