Particularly by the time the Renaissance discovered courtly love, there was a strong component of Platonism in it. For Plato, we are attracted to Beauty. Beautiful things or people are simply examples of Beauty itself. The thing about Beauty is that we are attracted to it, that is, it draws us to it. So, when a person is in love, the love is actually of Beauty itself, not of the specific example of beauty. If we recognize that this is true, we are drawn up to the level where we can truly contemplate that which we desire, and we become clear about our desires as well. Beauty properly pursued makes us pure. And, Beauty is perfection, which draws us to perfection as we draw nearer to it.
For Plato, that coincides with our contemplation of the forms. So, the intellect and the will come together, and we truly know what we desire, and we desire what we know.
Irving Singer (The Nature of Love, vol. 2, 23ff) gives five characteristics of courtly love:
1. Sexual love between men and women is in itself something splendid, an ideal worth striving for. This is a change from what came before. Plato, long before the mediaeval idea of courtly love, thought that love was the greatest of all ideals, but that it did not fully show itself in relationships between men and women. Homosexual relationships came closer for him.
2. Love ennobles both the lover and the beloved. Everyone took a male-dominated society for granted, and so the lover was the man and the beloved (passive) was the woman. "The lover and beloved both enjoyed a distinctive nobility that could not be reached in any other way. ...sexual love would make people better, finer, more likely to realize their human nature."
3. Sexual love cannot be reduced to mere libidinal impulse. It was an attunement between souls which could not wholly be accounted for in physical terms. To reduce love to sex would not have been to ennoble either person.
4. Love pertains to courtesy and courtship but is not necessarily related to the institution of marriage. This doesn't mean that it was just about an extramarital affair. However, the relationship one had with a spouse is not necessarily a relationship of passionate love, in this version of love. Since many mediaeval marriages had little to do with free choice, courtly love celebrated two lovers who chose each other freely, whether that was within marriage or not.
5. Love is an intense, passionate relationship that establishes a holy oneness between man and woman. This may seem obvious to us, but it didn't to the mediaevals. Previously, passionate oneness was usually associated with religious love. It was not about reaching the divine.