Groom to struggle with libido leaving party in confusion (9)
I believe the answer is:
imbroglio
'confusion' is the definition.
(I've seen this before)
'groom to struggle with libido leaving party' is the wordplay.
'to struggle with' indicates an anagram (letters move around or struggle).
'leaving' is a deletion indicator.
'party' becomes 'do' (do is a kind of party).
'libido' with 'do' taken away is 'libi'.
'groom' anagrammed with 'libi' gives 'IMBROGLIO'.
'in' acts as a link.
(Other definitions for imbroglio that I've seen before include "Confusion" , "Jumble" , "Complicated situation" , "Confused situation results" , "Confused and tangled situation" .)