He cannot appeal the PFA since he consented to the current supervised custody schedule. If he wants to amend the Order, he should retain an experienced family law attorney to discuss this matter and to file the necessary documents. When seeking an attorney, he may want to consider someone who has experience handling family law and criminal matters since there are pending charges against his former spouse that could have an impact on the custody issue.
My response is based solely on the limited information contained in the question. It is not meant to substitute your attorney's advice.
I agree that you cannot appeal the PFA Order. You could file to modify its terms, but your children are better served if you pursue custody. It appears from your post that you agreed to the PFA without admission of guilt. Unless there was some reason why your visits with your children needed to be supervised and it was not just something you agreed to, you be successful in modifying the custody terms in the PFA Order. I would seek the counsel of an experienced family law attorney in your area to discuss a strategy for pursuing custody of your children. Good luck.
I just want to add that a current charge under § 6312 will reflect very negatively upon the mother who is charged with possession of child pornography. If you want more custody for yourself, you may file a petition to modify the custody order. If convicted, she will be subject to Megan's Law 15-year mandatory registration as a Tier 3 sex offender.