Life has taught us that love does not consist of gazing at each other but in looking outward together in the same direction.

[L’expérience nous montre qu’aimer ce n’est point nous regarder l’un l’autre mais regarder ensemble dans la même direction.]

Antoine de Saint-Exupéry (1900-1944) French writer, aviator

Wind, Sand and Stars [Terre des Hommes], ch. 9 “Barcelona and Madrid (1936),” sec. 6 (1939) [US ed., tr. Galantiere]
    (Source)

(Source (French)). Usually given as:

Love does not consist of gazing at each other, but in looking together in the same direction.

[Aimer, ce n'est pas se regarder l'un l'autre, c'est regarder ensemble dans la même direction.]