re: Hell hath no fury like a woman scorned.

Had a family member go through this. It's awful. The mother spent a lot of time telling the child Dad was awful and, as a result, he didn't like coming to his dad's too much sometimes, plus she would cry and whine about being alone, so he felt guilty and would choose to stay with her often as he got older. However, he finally asked his father about some of what she said. All this time, the father had taken the high road and never spoken ill about the mother to the child. The child acknowledged that. I think the father eventually let him read a deposition and look at some texts the mother sent which were BS. Kid came to realize his mom was a biotch. Still loved her, of course, but didn't believe her BS any longer.

Document everything. Every cent you spend on the child, every medical bill, every request to see her etc... Stay on the high road. Don't say or write anything anywhere which might hurt you. Don't do anything stupid. Get an attorney and get a custody agreement. You'll get a child support order, also.