Can My ex claim "file" taxes when she didnt have a job.. nore any income? can she do that in anyway?

I have been supporting me and her for the last 2 years. she hasnt had a job that whole time. every year i go to claim and she tells me i cant. and that shes going to...? how? this would be the second time i claim my daughter and her as head of house hold. she tells me i cant. I say i can. I wont claim her but i will still claim my daughter. she tells me i can get in **** if i do? i need a answer to this pronto. thanks for your help..