It is a very interesting question. Although continued residence (CR) for unmarried partnership is not mentioned in directive 2004/38. It does say that host member state shall facilitate entry and residence in accordance to its national law. In Netherlands registered partner (RP) and unmarried partners (UP) are not discriminated. Therefore under dutch law registered partner do have continued residence after 3 years of living together with the EU national including at least the past one year in Netherlands PROVIDED they can prove they will not be a burden to the state by having either work, self sufficiency etc. Therefore technically as a unmarried partner of a EU national, the dutch authorities cannot treat you any different as compared to their own national law where it does provide CR for RP as well as UP.
Unofficial Source:
https://migrationlawclinic.files.wordpr ... t-2014.pdf