In an ideal world, a relationship would be like a perfectly-balanced see saw. Each side would be of the same weight and when one side went up, the other would go down (pause?) to compensate. No one side would ever be above the other; instead there would be the perfect, harmonious balance that has everyone on equal footing at all times.
In the real world though, we know that relationships don’t work that way. In most romantic relationships, there is a lover and a loved. Sometimes that just happens organically and other times it’s by design. Sometimes the titles shift fluidly from one partner to another as the relationship grows and develops. But always, there is a balance of power.