Divorce Advice for Men | Fathers Rights Divorce | Child Custody

My ex-wife and I went back to court two months ago to change custody from "partial" to "shared" custody because I moved closer to be with my son (I would like to have full custody, but we all know how hard that is to obtain). My ex-wife's boyfriend (who she met on the Internet three months prior) moved in with her and my son. Also, living in the home is her friend and her friend's daughter. I currently pay child support from the previous child support/custody order. There are currently three incomes in her household along with her two jobs that she is paid "under the table". After the custody hearing was agreed upon, I filed for a reduction in child support - actually hoping that I will not have to pay any child support to her - and he would be cared for equally by his mother and myself. I would not mind giving her money for my son, but she does not use it toward him. He is always wearing clothes that are too small, torn, or stained. However, she has four vehicles, a new driveway, two new fences, and a new garage door. I love my son, but the only way that I will be able to care for him under shared custody is by having at the money back in my pocket to provide for him correctly. Do I have a good chance of winning in court? I cannot afford a private investigator, but I do have a friend that is willing to follow her to her "under the table" jobs to take pictures of her. Should I take him up on his offer? She was caught lying in court twice the last time, but my child suppport was increased. Please help.