This circle idea is about having common goals about the things that affect the marraige. Children pass through a marraige, and are not part of the circle. They are part of the second ring but it is just you and your spouse that is deeply inside the circle.
Protecting this idea means that when you allow things – people, children, desires – to get between you and your spouse they are inside the circle. The practice of being aware of what is between you that should not be between you creates a closeness that is very healthy.
Between means that you don’t let others or things take priority over the spouse.
Temporarily this might happen when the circumstances call for it. Sickness, temporary job needs, or just life. These things that you might differ on in the moment, must take a back seat at some point and be discussed in order to keep the circle pure.