I am the father.How do I get joint custody of my daughter in the state of Nebraska?

I am the father.My ex and I share vistation(like joint custody) she is now going through the courts, unlike we planned. She is getting state aid, all she wants is child support, basically for me to pay her pills because she doesn't work that much. I was the sole provider for the 3 years of my daughters life. I have health insurance on. Do I have to pay child support even though I would like to have joint custody. She threatens to take away my daughter if I introduce to my girlfriend. I always have to ask her for permission to do anything with my daughter because if I do not she threatens to take her away, starts yelling and using profanity in front of our daughter. - Is this your question? Add additional information