Room where Barbie's boyfriend entertains desire (7)
I believe the answer is:
kitchen
'room' is the definition.
(I know that kitchen is a type of room)
'barbie's boyfriend entertains desire' is the wordplay.
'barbie's boyfriend' becomes 'ken' (I've seen this in another clue).
'entertains' is an insertion indicator.
'desire' becomes 'itch' (itch is a kind of desire).
'ken' enclosing 'itch' is 'KITCHEN'.
'where' is the link.
(Other definitions for kitchen that I've seen before include "Place to prepare food" , "Cook's room" , "where food is a concern" , "Room for preparing meals" , "In workplace" .)