Ainur marriages and what comes after

[Mithalwen]

Well since I was posting from work I didn't have the books ... However remember that certain of the valar were regarded as siblings because they were coeval in the though of Eru? I think the spouses were the vala who were complementary . Aule and Yavanna are both creative it is just Aule is creative wiht minerals and Yavanna with plants so their needs conflict at times.. Also at the Maiar level of Uinen reining in Osse.

As for Melian - she had to take in a physical body to marry thingol and produce Luthien. Otherwise the forms of the Valar were less tangible if I understood correctly... a kind of clothing in order that they might be perceived by the children of Iluvatar... can't help thinking of them as holograms!!! Since the Istari also had to take on "proper" bodies, I guess they would be theoretically capable of begetting children - but then since they got stuck with the bodies of ancient beardie weirdies and in temperament were grumpy, creepy, and "I talk to the trees" odd.... I think it is very much an academic question