If my ex-wife left the state leaving our son while we are going through a court battle, is this considered abandonment?

It depends on how long she is gone, whether she is sending support etc. However, if the child is with you and the mother moved out of state, you should go to court immediately and get a temporary parenting plan that places the child with you the majority of time and sets certain conditions for the mother to see the child, e.g. disclosing her address.