The source cannot marry Its Own "Internal Potency" , as the "Internal Potency" by very definition is Internal to the source.
both are the same, its like seeing the same object with two different comprehensions.
Only expansions of Radha, thus extending the potency and manifesting externally can marry. how is this possible. Radha is Krishna's Internal Potency, Please understand what this internal potency means. at this stage, any kind of duality cannot be applied, not even the primal duality, which engulfs everything including the Vishnu , Shiva and Maha-Vishnu, Ananta.. all other manifestations, like Devi, Lakshmi etc etc etc are expansion of Radha, as the manifesting potency.
But not Para-Tattva. even the primal duality of constituent and whole does not exist , in the state of Vaikunta. it is turiyateetha ( beyond turiya ).
my god, i thought for too long whether to answer this question or not, not because i was scared people dont get it, but i was REALLY scared that people will get it wrong, but i have finally answered this for the lotus eyed one, the achyutha, the one who is really infallible, the ever glorious, the Anantha, hari, for that Brahma Purusha , for that Param Brahma.
Harirnama Harirnama Harirnama Kevalam.