The "reality of relationships" is that relationships measure the distance or proximity between two things.
Theoretically a relationship measurement exists even when there is no proximity between the two items being compared or discussed!
That is the beauty of measurement -- it quantifies in a very real sense the strength or proximity of the relationship in such a way that anyone else who wants to make the same comparison can measure it in the same way that anyone else measures the relationship and they will obtain the same result.
A good example is the relationship between one's self and God:
At the nominal level of measurement, one concedes the theoretical construct of God, so by definition "God is!" An atheist may claim that their is no such entity as God but by the mere fact that they acknowledge the concept of God, the atheist creates God's existence. The fact the atheist may not want to have or acknowledge a relationship with God does not negate the existence of the theoretical concept "God" that the atheist wishes to deny.
At the ordinal level of measurement, not only does God exists, the relationship one has with God is greater than the relationship an atheist has with God. The atheist by definition denies the existence of God but has to acknowledge the theoretical construct in order to deny the absence of a belief. The absence of the belief has more to do with the powers and description ascribed to God rather God's actual existence.
At the interval and ratio levels of measurement, it is more difficult to measure the relationship. A quantitative measurement scale would need to be constructed in order to measure the relationship between an individual and God at the interval or ratio level of measurement. Such a scale could be constructed and based on various thresholds of pain going from the extreme of either the absence of pain or the euphoria of pleasure to the other extreme magnitude where the level and intensity of pain is such that it causes the individual to give up its life to escape the pain.