Family Law Questions? Ask a Family Lawyer Online.
Has any custody order been given on the child?
Are you and the mother legally married?
Do you have the child with you right now?
OK the law stipulates in PA that whomever has the child as physical custody of the child. Since you are married you both have custody of the child. You are not required to give the child back to her.
If you feel she may take off with the child again you can keep him and file a petition with the courts for temporary custody of the child until the problems are resolved or a until you file for divorce and get a final hearing on custody of the child.
I am assuming she wants you to give the child back in the near future, if you think she may take off I would not advise returning the child unless this is what you wish to do. I would advise you to get in contact with a family law lawyer in your area to begin the process of seeking temporary custody of the child or allowing her to have custody and seeking visitation.