“Most important, you are not alone. With you, beside you, interlocked in you are others. They do not have names, nor are you aware of them as shapes, but you know them and you are bonded to them with a great single knowledge. They are exactly like you, they are you, and like you, they are Home. You feel with them, like gentle waves of electricity passing between you, a completeness of love, of which all the facets you have experienced are but segments and incomplete portions. Only here, the emotion is without need of intense display or demonstration. You give and receive as an automatic action, with no deliberate effort. It is not something you need or that needs you. The "reaching out" is gone. The interchange flows naturally. You are unaware of differences in sex, you yourself as a part of the whole are both male and female, positive and negative, electron and proton. Man-woman love moves to you and from you, parent-child-sibling-idol and idyll and ideal—all interplay in soft waves about you, in you, and through you. You are in perfect balance because you are where you belong. You are Home.”

Source: Girls in Their Married Bliss

Source: Looking for Alibrandi

Source: To All the Boys I've Loved Before

As quoted in How to Be the Employee Your Company Can't Live Without : 18 Ways to Become Indispensable (2006) by Glenn Shepard

Appearance on The Howard Stern Show (1987).

Source: Howl's Moving Castle

Variant: Love who you love while you have them. That's all you can do. Let them go when you must. If you know how to love, you'll never run out.
Source: My Name Is Memory

Source: Cosmopolis (1892), Ch. 1 "A Dilettante and a Believer"

Source: Tiny Beautiful Things: Advice on Love and Life from Dear Sugar