I've just looked over the Dwarf materials earlier on tonight.
The source of the first half of
Aule and Yavanna is covered in HoME11,
Latter Quenta Silmarillion, pages 203-215 (Harper Collins MMPB). CT takes us through the evolution of this text and the variant versions, but for the purposes of this question the important points are:
- Durin not having a spouse is an earlier concept: the reason is that Aule had originally made one Dwarf (Durin, the eldest), then six other male Dwarves (the other Fathers), then six females, then he got tired and rested (lazy sod!)
- The final text is that published in the Silmarillion, which CT dates to 1958, and in which the separate making of female Dwarves and the idea of Durin sleeping alone are not present.
- CT concludes that the Dwarf material is all datable to roughly the same time and assigns the order: first draft (6+1), letter to Rhona Beare (6+1), final text (no 6+1).
- CT interprets the "he had no companions" note in Of Dwarves and Men to mean that the other fathers were set down in pairs, and so they had 4 awakening places: the Firebeams and Broadbeams in the west, the Ironfists and Stiffbeards in the east, the Blacklocks and Stonefoots also in the east, and the Longbeards on their own in Gundabad; this interpretation is consistent with JRRT's presentation of the text and there seems no reason to question it.
So the answer is that Durin not having a spouse was an older concept that was abandoned. The final concept was that the Longbeards awoke in isolation, whereas the others awoke in pairs, but the matter of whether or not each father had a spouse is not entered into.