Pretty sure the only reason JJ wrote it that way (“we’re a dyad in the force”) is because of a couple lines from TFA.

Kylo asking his officer “What girl?”, which gives the impression that he is aware of some mysterious girl out there that he keeps having visions/dreams of.
Kylo saying “It is you.” in early drafts of film TFA after Rey gets Anakin’s lightsaber. The line still appears in the novelization and is voiced by Adam Driver in the lego game. The line implies once again that he has had visions of her or knows there is some sort of connection between them.