The one-to-many and one-to-one relation are implemented in a slightly different way.
Object (objectId) ObjectCharacteristics(charId,objectId)
The order of the table is not important:
Husband (husbandId) Wife(wifeId,husbandId) + unique constraint on husbandId
N.B. One-to-many relation is also a one-to-one relation in the order way. The ObjectCharacteristics has one and only one object.
But you are right the relationship is a concept that does not depend upon the specific data in your database but only on the structure of it.