In 1831 Belgium was created out of what had been part of the Netherleands. It failed largely due to the language/identity divisions within the country.
So, is there any way Belgium could hold itself together to the present day?
I think it would have a better chance if it wasn't a Republic* and if it hadn't include Luxembourg and Limburg, without Limburg and Luxembourg German Nationalism would have been a lot less succesful in the Republic**, and it's likely that Flemish would either have become their own Nation or could have been assimilated by the Walloons.
*The fact that it was a Republic meant that it was seen as a threat both by the French, Austrian, Russian and the Prussian and noone of them was willing to guaranteed the continued neutrality proposed by the English
**Especially Limburg served as a centre for the German Nationalist movement.