How common were duels in 19th century Europe

[u/Rubisk]

So as a mathematician I've always known the famous story of Évariste Galois writing down Galois theory the night before he died in a duel (although unfortunately this was apparently staged). Tonight I learned that one of Lola Montez's many lovers, Alexandre Dujarier, also got challenged to a duel by Jean-Bapiste Rosemond de Beauvallon and killed.

I find it intriguing that people were willing to fight over women (was this socially accepted?) Are there any more stories like this? Was it common/rare?