Even though for the purpose of lila (pastime) it says Krsna created Radharani, in actual fact She is eternal like Krsna and always has been with Krsna because She IS Kṛṣṇa.

 On the Absolute level, even though it is said Krsna created Radharani, in actual fact, She is ALWAYS part and parcel of Krsna, Radharani has always eternally existed with Krsna.

In the spiritual world there is no past or future detection of time, there is only the "eternal presence." 

So, even though for the purpose of lila (pastime) it says Krsna created Radharani, in actual fact She is eternal like Krsna and always has been with Krsna because She IS Kṛṣṇa.