From “Brain Pickings,” a blog by Maria Popova – first, Popova quotes Rilke:

“I hold this to be the highest task of a bond between two people: that each should stand guard over the solitude of the other.”

Then Popova begins her blog post:

““Love one another but make not a bond of love: let it rather be a moving sea between the shores of your souls,” the great Lebanese-American poet, philosopher, and painter Kahlil Gibran counseled in what remains the finest advice on the secret to a loving and lasting relationship.

Our paradoxical longing for intimacy and independence is a diamagnetic force — it pulls us toward togetherness and simultaneously repels us from it with a mighty magnet that, if unskillfully handled, can rupture a relationship and break a heart. Under this unforgiving magnetism, it becomes an act of superhuman strength and self-transcendence to give space to the other when all one wants is closeness. And yet this difficult act may be the very thing — perhaps the only thing — that saves the relationship over and over.”