First and Last Love

Love…
…the first time is like nothing else. Love the last time is beyond even that. First love arrives in youth when it is hoped for and even expected. Love the last time comes unexpectedly after one has lost hope of it ever appearing again.

Theoretical physicist and philosopher Albert Einstein
How on earth
are you ever
going to explain
in terms of
chemistry
and physics
so important
a biological
phenomenon
as first love?