LotR --- Appendix A: I, (iv) -- Gondor and the Heirs of Anárion

[Aiwendil]

Maybe it was one founded on mutual respect and understanding where they were both 'placed' within the relationship , almost as though they were a 'complement' to one another.

This reminds me of a quote from "Myths Transformed" about Manwe and Melkor:

He [Melkor] was to make / devise / begin; Manwe (a little less great) was to improve, carry out, complete.

. . . which seems to hint at a similar complementarity between those two, the original brothers of Ea.