Ex Husband in Violation of Court Order

My question involves a child custody case from the State of: PA

My Ex Husband loves to entertain his girlfriend in front of my children and as per the court order he had his attorney put a clause that states, "no one that you are intement with is able to spend the night when you have custody of the children". I have confronted him of this and he now feels it is a stupid rule, although he is the one that had it added. I have also confronted his girlfriend as well telling her exactly what the court order says and she just laughs. His response to all of this is that if I take him to court the judge will just laugh and see that it is a stupid clause and remove it. He first wanted to have the clause because he wanted me to not have anyone in my life, but it has now come back to bite him in the A$$. My children are visiting him now and when I talked to my children again tonight as well as two nights ago I recorded our conversations, and both children stated mommy his girlfriend is spending the night. Tonight I got it recorded that he drove them over 140 miles to her house in Woodbridge, VA to spend the night at her house as well. After talking to my children I asked to please speak to their dad and when he got on the phone I reminded him again that all calls are recorded and so is the current conversation we are having. He said "yea yea they always are and I am aware of this, what do you want." I told him, "you are in violation of a court order and you know she is not suppose to be spending the night with the kids when they are in your custody." He didn't defend himself and say we are not spending the night and there is never any emotion on his part. The only thing that happened is him saying "Good Bye" and hanging up on me. There is so much more happening like his GF answering the phone and not letting me talk to my children. I provided my children with a cell phone and their father took it away and won't let them have it. This is just the tip of the ice burg of a mount of issues with my Ex who is a true narcissist. If I take it to court he already said he will make up whatever is needed to get me fined if I take him into court. Although I have neighbors and family members to back me up that I do not have anyone living with me or spending the night when I have custody of my children. Please give me your thoughts.

How old are the children involved?

My children are 7 and 9 yrs. I already have a time that I will be going up to the court house this up coming week and will be there pretty much all day filing paperwork for mediation and am also going to try and get a home study as well as changes made to the current court order. I know and undertand that this will not happen over night but I must try and do something. I really do wish that they would do something like surpervised visitations until all of this is resolved.