One of the exoteric meanings of The Lovers in the RWS is human (not excluding sexual) love, but the primary interpretation is esoteric, regarding the complementarity of the masculine and feminine (yin-yang) principles in the psyche. My main beef, however, is with the notion that the primary meaning is choice. As Adam and Eve are the only human beings in the Garden of Eden, there is no possibility of choice about whom to select as a partner. Of course, there are always choices of some sort involved, especially in matters of love and marriage, but almost everything we do involves choice.
I think the association of The Lovers with choice goes way back in history and is due to a misunderstanding of the symbolism of The Lover in older Tarot decks such as the Tarot de Marseille. In the following, I will refer to the popular Conver Tarot as reconstructed by Paul Marteau in the Grimaud Ancien Tarot de Marseille, of which a scan of The Lover is attached.
The are four characters in the image: Cupid, a young couple, and an older woman. Note first that Cupid's arrow is aimed at a point between the homely pig-like guy and the pretty woman. Cupid's attention is obviously on the young couple. In interpreting the Marseille it is important to take into account the details, such the direction in which the characters are looking and the positions of their hands. Note the hands of the young woman. Her receptive (left) hand is over the heart of the pig-man; her projective (right) hand is indicating her pelvic region. Both the man and the young woman seem to be paying attention to the older woman on the left, who may be royalty, as there is something like a crown on her head. In any event she appears to be a person of some authority. Her body language (note the position of her hand on the man's shoulder) is that of a friend giving advice, perhaps a counselor or relative. (In the 1JJ Swiss deck, she is depicted as an old hag in the background and would appear to be a matchmaker rather pleased with her success.)
Therefore the plain sense of the image is that of a young couple in love, possibly engaged, receiving counsel (perhaps about marriage) from an older friend, relative, or advisor. Choice as a primary meaning is really too much of a stretch here.
ETA. I just noticed that Sulis has the same idea about the "choice" interpretation originating with the older decks. I chose the Grimaud Lover for the attachment because the hair of the young woman is much prettier than in the Conver facsimiles or the CBD.
I love this card. It is probably my favorite card in the Conver deck. There is something so human, warm, friendly, and familiar about it, at least according to my interpretation. It makes me feel good for some reason.