This card depicts an embracing couple. The fact that they are of different colour depicts, on one level, simply that opposites attract, and that where there is a reconciliation of dualities, each becomes more complete, like the yin and yang of Chinese thought. The symbolism, however, has something more concrete to say about the eros principle.
Romantic love has not necessarily always been the prime factor behind most marital choices. More usually, marriages were made - and still are made in many parts of the world - to cement the fortunes of the families concerned and was thus more often or not a political move, economics and status being a more consideration than love. Romance was more likely to be considered a dalliance to be outgrown in time, and jealously prevented for young girls, where maidenheads might constitute too high a premium to lose.
Possibly this started to change - in Western culture and literature at least - most notably with the culture of the Troubadours. In fact, the spiritual quest of the Troubadours involved a form of unrequited love; the knights serenaded their unreachable ladies because this purified their souls onto a more elevated plane of awareness. This is an image of the Platonic - or Geminian - soul, trying to seek his or her immortal counterpart. Eventually, novels like Clarissa made sure that the romantic quest was to become a destiny for two Eros-stricken Questors, where both had to vanquish the dragons of jealous, plotting adversaries and dire economic crises before reaching the bridal chamber in one piece.
Jungians have suggested that this form of dealing, or fate, is necessary for the evolution of the soul. It is only through the activation of the inner masculine or feminine image, which the beloved fulfils, that the soul of the individual might break away from the repressive values of the collective. This is a theme which has proven itself many times as a staple in soap operas as well as in romantic novels.