Divorce decree please help

I been divorced 4 years. We split the child 50/50 and alternate weeks. We are supposed to alternate tax season. My ex has not worked the whole time up till 3 months before the year ended. She tells me she filing taxes and if I do she will take me to federal court. She has failed to follow the decree except visitation. I have my child more nights and I buy all the clothes for both homes every tax season. And the mother is unemployed again she only worked to try to file taxes then quit. I already filed 2 weeks ago and she hits me with this today so am I in trouble