La Petite Mort was actually
believed to be a cause of
death at the time. It was believed that having
too much sex could lead to death. There are many
references to this in old
manuscripts, most notably
Chaucer's "
Canterbury Tales".
As to
why they thought this would be believed,
I do not know for certain. When I asked my
english teacher (who is very big on
english history) she said she didn't know the
reason, but offered "These people were very big on their bodily fluids". Visions of "
Doctor Strangelove" begin to come to
mind.