For many years, a classic argument about the Middle Ages was that people-back-then were not as loving as we moderns. They were so used to children dying, they learned not to care much. All their marriages were arranged--oh, well, whatever, that was what marriage was.
It is true that "people back then" were not exactly like us. As an amateur historian, I struggle with the gap between cultural/period mindsets and the consistency of human behavior. We may have a hard time completely understanding the medieval mindset. We don't have any trouble understanding Hamlet's worries, Juliet's ardor, and Benedick's defensive uncertainty.
In addition, solid research by scholars such as Antonio Fraser (The Weaker Vessel) illustrates that people in the past, rather than being emotionally hollow or stunted, experienced love and affection and intimacy and closeness. They mourned their dead children. They wished for tenderness with a person who "got" them.
Granted, their language and expectations were greatly different from our own. Romeo and Juliet perish. Numerous other Shakespeare couples suffer separation until circumstances prove the characters worthy of affection.
Elizabeth's declaration to Lady Catherine de Bourgh in Austen's seminal work--"He is a gentleman; I am a gentleman's daughter"--is both a reflection of that older mindset and preparation for a more modern one. The older mindset is only going to pair one member of a particular class with a member of the same class. The more modern mindset declares that Elizabeth doesn't have to prove her worthiness; it is inherent.
The point here is that while the way a person dealt with a particular emotion--such as love--was different in the past, the emotion was not. And the same is true in our world today. People from different cultural backgrounds may handle, say, confrontation in different ways; the feelings that lead to confrontation are the same and always relatable.
The same is true of love. Certain events and tropes and expectations within Japanese light novels and manga may be unlike Westernized customs. When I read them, I am granted a different perspective. Yet the emotion that fuels the acts is the same.
In sum, humans are not stuck in compartments. We can communicate beyond our nurture and nature. We can understand poetry and literature from other cultures as well as other times. We can understand our ancestors' romantic desires and needs. We can share their hopes and fears.
As Marilyn Yalom writes, love may not have always used the same icons, but the emotion--and its effects--have always been with us.