Romantic relationship only, or are you interested in other kinds? For example, my brother and I were estranged for many years and have just started to get to know each other again the last couple of years, and it's been a funny old game, negotiating this 'similar but different' thing between us.
I think I read somewhere that ENFP is INTP's 'counterpart' - plays the same part but in a different 'dimension', whatever that means... and if INTP and ENTP are very similar, sorta internal/externalized versions of each other in many ways, this might be a key of sorts to unlocking the ENTP/ENFP thing.
Ils se d�merdent, les mecs: trop bon, trop con..................................MY BLOG!
"When it all comes down to dust
I will kill you if I must
I will help you if I can" - Leonard Cohen