Love, as we know today was invented by the English(along with ambition and happiness) and in particular by Shakespeare. So says this
article. I don't have much idea and I haven't read Shakespeare in original. But according to the author;
Today, of course, this most powerful feeling is familiar everywhere within the so-called "Western" civilization (which includes all societies based on monotheistic religion, i.e., Judaism, Christianity, and Islam) and it has penetrated into other civilizations as well
That certainly carries some weight in Indian context as one can observe that the passionate love songs in Hindi movies are the works of poets with Islamic background (including Atheists and Hindus with education in Urdu).
Anyway, non-articulation of this emotion need not mean non-existence of it in other societies (but for practical purposes could be as good as non-existent) or in England prior to the sixteenth century.
The characteristic of true love that Shakespeare stresses in this sonnet is its unchanging nature: it is one-in-a-lifetime passion. Admit it: this is what we all want, however difficult it proves for most of us to find. Those who argue that our desires are genetically, and therefore, evolutionarily determined, should consider that; it is far more likely that we share our genetic endowment with the clearly polygamous apes, than with species genetically remote from us, such as wolves, penguins, or swans, who mate for life. Yet, we long for a monogamous lifetime relationship.
I guess here the author confuses love with lust. However, I believe even a person in love can fall in love again with some other person simultaneously. Didn't Levin fall in love with Anna when he was still passionately in love with Kitty? In the case of unfaithfulness in lust, when a person lusts after more than one person, it requires action from his/her part to truly become unfaithful. However, unfaithful love is a natural phenomenon as it doesn't require any physical contact. It's easier to become unfaithful in love than in lust. There exists freewill in lust but not in love.
But I believe one-in-a-lifetime passion isn't supported by the "scientific" studies too. I guess it's been measured that love lasts only for one and half years and after that one needs regular sex or some mutual work to keep that oxytocin running in the relationship. But of course, the narrative could be changed if it's always in love and not always in love with one person.
Then the author ends with this absolute mystical flourish. I suppose the field of psychology badly needs scientific validity just like
psychiatry so as not to get into these unverifiable.
In short, love makes it possible for every one of us to find one’s proper place in the world and to define oneself. It leads one to the discovery of one’s true identity (we often say that we find true understanding in the loved one, someone who really understands us): one’s identity, one’s true self is found in another person, in what he or she sees in one. This other person, immediately recognized (thus true love is love at first sight), then is recognized as one’s destiny, the One, and finding love at once also becomes self-realization, giving meaning to life as a whole.
The way I see it the feelings of love and lust could be felt from your early childhood. The passion could only go up when one reaches his/her puberty but I believe one can distinguish between love and lust even before that. Also, even after coming of age, the raging hormones don't adulterate the feeling of love. However, since the society around doesn't articulate it for you, probably, one could be confused about those feelings and could think it's another form of lust. I'm not sure the idea of understanding or identity influencing coming into picture in any of these.