A pendulum swings past center before it settles. After a fight, couples overcorrect, swing back, then overcorrect less—until they finally find equilibrium. Recognizing the oscillation is the work.
An object in motion stays in motion until acted on by an external force. Relationships work the same way—it's far easier to keep one moving than to restart one that's come to rest.
In a relationship, you and your partner play driver and engine in turns. Both burn energy. Asking for space isn't withdrawal—it's the engine cooling down so it can keep running.