Or at least a Zener diode. A voltage divider generates known potential with zero current usage. As soon as you start drawing current, voltage drops. So you either use weak resistors to provide enough current (and a lot of it goes down the drain), or try to calculate the divider treating the device (EEPROM) like one of the resistors, except current taken by it may vary strongly by operation it performs so the voltage will float a lot.

And if you can't get your hands on a dual voltage regulator, you always can use two regulators, one for 5V, one for 3.3.