I think it doesn't exist in human world. What so called "love" is simply "trade" behind the disguide, especially the shit soap comedy on television(tell lies vision).
Don't be tricked.
"Marriage" is another kind of sexual trade in a word with beautified concepts.
What the romantic love stories tell us are just fabricated sugar-coated shits.
They may seem so real because so many realistic senses are interspersed among the plots, but they are actually illusions as macroscopic view, even are hallucinations.
The purposes of all those shits are to burn your life, drink your blood and devour your soul.
This is a ultimately sophisticated form of enslavement.