You should consult with a lawyer regarding the best legal way to resolve this issue. Immigration Laws are enforced at the borders, not the place one should wait to find out about if there are any "...additional serious risks ..." resulting from US PR abandonment.
I f I understand you correctly, an ex-girlfriend is making false allegations that your marriage was a sham for you to acquire a green card and you are denying those allegations. If you are in a bona fide marriage and can prove it to USCIS, there is no need for you to be worried.
I represent parents in DCPP a.k.a DYFS cases. Each defendant is appointed an attorney by the State of New Jersey if you can't afford one. Consult with an attorney. This is not the forum to address allegations and other issues related to your DCPP/DYFS case.
I am assuming by "permanent residency" that you are referring to LPR status. Your wife is not eligible for adjustment of status in the US based on your LPR/Green Card Status. Consult with an Immigration Attorney to find out what are her available options.