Well, good luck, it sounds like if she is new she might be in love with the very idea of poly itself. NRE for poly. Thing is that damage can occur in its wake. Damage can occur with any unchecked NRE really. One has to be very considerate, keep feelings and actions in check and go very slowly. We poly's don't get to let loose with NRE like single (no kids) mono's do. Too bad for us! LOL
Yup, sounds like a good long honest and open discussion about what's going on is your best bet.