95% of the literature seems to suggest the first is correct. However,
I've seen a few British and Australian academic papers that use the
latter.
Which is correct and more importantly, why?
Assuming you've seen enough uses of the unhyphenated form that it
can't be dismissed as an aberration, both are correct, because both
are in use. Spelling is conventional. "Spelled" and "spelt" (grain
aside) are the same word with two different spellings, both correct.
Same for "honor" and "honour."
Sometimes the convention varies from place to place, as is true of my
examples. In such a case, use the form used by the people you are
writing for. If that won't work, use the one that feels better to
you.
In general, the tendency in English is to start with two words (base
ball), hyphenate them (base-ball), and eventually join them without
hyphen (baseball). That seems to be what's happening with
"well[-]being."
--
Bob Lieblich
Alright?
As you may have noticed, solid words are gaining ground over discrete
or hyphenated ones. Thus, "being on line" is nowadays generally
rendered as "being online".
CW