Establishing an Order: International Custody Disputes After Paternity is Established

My question involves paternity law for the State of: Wisconsin

My situation is rather sticky. I have scoured law text for hours and can not seem to find anything relative to my situation.

I was in a relationship with a man who is not a US citizen. He is a citizen of the Netherlands. After finding out I was unexpectedly pregnant, he insisted that I moved to Serbia with his parents and raise the child there. When I refused he became aggressive and violent and threatened to hide the child in another country and so forth. He was not present for most of the pregnancy nor the birth. He is not on the birth certificate (no one is besides myself) and has not otherwise been established as the legal father. He has come to the US once to see the child at six weeks of age. He has since emailed on average once or twice a year asking for pictures and such, I did not respond. The child is now 5 years old and he is now threatening legal action. I am torn as I have worked hard to create a stable life for my child and she has been raised for over three years now by my current husband who she knows as 'daddy'. She has a very nice life and a wonderful family and a new sibling.

I am wondering what his rights are if he were to establish paternity? I am still fearful that, if given the opportunity, he would take her to another country where I would not have any rights to search for her. Will a court allow him to have unsupervised visits? I'm just scared for my child and want to do what I can to maintain the normalcy and stability I have been able to provide her thus far.

Thank you in advance for your support and advice!

**side note : he has provided some financial support over the years and it was not ever requested **