Linda Goodman's Love Signs

During these periods of being apart, however brief or however extended, both persons are lonely, empty and incomplete. Yet even throughout any such temporary spaces in their togetherness, there’s a constant, pulsing astral communication between them—for even then, they are linked by a cord that connects them over the miles.

those which God hath joined together, let no man put asunder” refer to such as these. Yet this warning is unnecessary, simply symbolic ritual, for no man can break the tie between Twin Souls, not even themselves. Nor can any energy in the Universe. The Force that created them is all-powerful and indestructible. The bond may be weakened, their final union and consummation delayed, but they cannot be separated permanently. There can be no end to the kind of happiness they may claim—when they wish to do so—on a timetable dictated by the Free Will choice of the Higher Angels of their own selves. (The Superconscious or Supraconscious of each.)
This kind of instant magnetic attraction is often called “love at first sight,” which is no accident of fate, but very real. It’s more than curious coincidence that Twin Souls, out of the whole huge world, should be drawn together at the appointed time. The crossing of their paths has been predestined on a Higher Level of Awareness. Certain spiritual energies are at work to bring about their meetings, as surely as the migration of birds and the return of comets are governed by a similar Universal Law. Their coming-together is controlled by the workings of Karma, which is but the sum total of Causes set into motion in the Past—and these determine infallibly the conditions of the Present. When the time comes for Twin Souls to incarnate, they are sent to Earth, clothed in flesh (again, the bodies being the Temples of the soul) through particular Time-Energy Forces, at the moment in Earth Time when certain planetary configurations create the proper conditions. These Time-Energy Forces are electro-magnetic in nature, yet more complex than this.
None of us can control the eventual results of the Causes we’ve initiated or set into motion in our past lives, although we can control our re-actions to the results such past Causes bring into the present lifetime. The “Free Will” to change these karmic events is possessed by the Higher Self, and we may attain such power by learning to tune into or communicate with the Higher Self (Supraconscious). But “Free Will” on a conscious level can only be realized in the Future—since, in the ever-moving stream called the Present, we are setting into motion, through actions we currently initiate and through our re-actions to past Causes—the future conditions we will inevitably meet.
As for which particular planetary influences in the nativities (horoscopes or birth charts) of two people reveal to an astrologer the indication that these are Twin Souls, they are too intricate to comprehensively explain in this book, in their entire scope. But assuming that such planetary influences are present in the respective charts of lovers, a destiny is revealed in which the two will meet involuntarily—and cannot be separated, even through the experience of death—except for temporary intervals of Earth Time in the present life, for the purpose of karmic soul-testing.

A man and a woman who are Soul Mates hardly need to speak the words “I love you,” knowing as surely as they do that they must belong to each other whether in this present incarnation (lifetime)—or (due to karmic complications) at the end of many more centuries. The words in the marriage ceremony