Acknowledgement Of Paternity

My ex of five + years is now asking that I take him to court In order to get child support. We had a verbal agreement that he pay 600 a month and I have proof of 12+ months of this payment. We were together up until my daughter turned four years of age.

When I found out I was pregnant I had told and discussed that he may not be the father of my daughter there was one other man. He and I both decided that he was going to be her father due to the fact we were in love and the other man was not a good person and we wanted to keep our family together. At birth we gave my daughter his last name and he signed acknowledgment of paternity.

As well as signed it a second time at domestic relations.My daughter is now 7 years old & has known only one father. He went behind my back on one of his visits with my daughter to Swab and take paternity to private place and has found out 100% that he is not her father? I do not want to traumatize her at the age of seven and I don't feel that it's fair to her as well. If we have to go to court what will happen?