If we go Dutch, it means that everyone pays for their own meal, drinks, entertainment, etc. when they go somewhere together. This can also be called a Dutch date or a Dutch treat.
However, this is commonly practiced amongst non-intimate friends, but can be considered stingy if it is a romantic date or even at a business lunch.
The origins of the expression are a bit cloudy. One school of thought says that it probably came from a Dutch tradition where in the Netherlands it wasn’t uncommon to pay separately when going out as a group.
It is also possible that the expression came about in England during the Anglo-Dutch wars to promote negative Dutch stereotypes. An other example of the latter is Dutch courage, also called liquid courage, because it requires large amounts of alcohol to obtain courage!