Plan to be used with the person I have broken with (8)
I believe the answer is:
conspire
'plan' is the definition.
(I've seen this before)
'used with the person i have broken with' is the wordplay.
I cannot really see how this works, but
'person' could be 'pi' (PI is an example) and 'pi' is present in the answer.
This may be the basis of clue (or it may be nonsense).
'to be' acts as a link.
Can you help me to learn more?
(Other definitions for conspire that I've seen before include "Plot secretly" , "So prince is given to plan secretly with others" , "Act secretly with others" , "'Plot, connive (8)'" , "Secretly plan together" .)