Desire is bringing wife and husband together (4)
I believe the answer is:
wish
'desire' is the definition.
(wishing is a kind of desiring)
'wife and husband together' is the wordplay.
'wife' becomes 'w'.
'and' means one lot of letters go next to another.
'husband together' becomes 'ish' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'w'+'ish'='WISH'
'is bringing' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
(Other definitions for wish that I've seen before include "Express a desire (upon a star?)" , "Desire, hope" , "Request - yen" , "prayer" , "bid" .)