It's tied up with romance (4,4)
I believe the answer is:
love knot
'it's tied' is the definition.
I can't tell whether this definition defines the answer.
'up with romance' is the wordplay.
'up' becomes 'knot' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' means one lot of letters go next to another.
'romance' becomes 'love' (I've seen this in another clue).
'knot' after 'love' is 'LOVE-KNOT'.
Can you help me to learn more?
(Other definitions for love knot that I've seen before include "Symbol of affection" , "Intricate token of affection" , "Something tied as an emblem of deep affection" .)