Alison and I are involved in affair (7)
I believe the answer is:
Here is my best explanation:
'affair' is the definition.
('liaison' can be a synonym of 'affair')
'alison and i are involved' is the wordplay.
'and' means one lot of letters go next to another (I've seen this in other clues).
'are involved' is an anagram indicator (involved can mean confusing or complex).
'alison' put after 'i' is 'ialison'.
'ialison' with letters rearranged gives 'LIAISON'.
'in' is the link.