there are two kinds of partnership: contract partnership or registered partnership. if it is the first case, you don't have share the financial responsibility but if it is the second case, you would, anyhow you can go to the notary ( notaris ) to make a statement saying that you two want to be financially independent...( or you can also make part of your property apart from the community property)
the most important thing is to go to the notary ( notaris in Dutch)