Love the various theatres that we appear in (10)
I believe the answer is:
sweetheart
'love' is the definition.
(I've seen this before)
'various theatres that we appear in' is the wordplay.
'various' indicates anagramming the letters.
'that we' becomes 'we'.
'appear in' is an insertion indicator.
'theatres' with letters rearranged gives 'setheart'.
'setheart' placed around 'we' is 'SWEETHEART'.
'the' is the link.
(Other definitions for sweetheart that I've seen before include "Term of endearment" , "baby" , "flame?" , "Boy- or girlfriend" , "Lover" .)