Need custody help

Not sure where to post this so sorry if this is the wrong spot. my now ex and i have a 4mo together. In the state of Wisconsin we had to do a paternity test to prove him the father because we aren't married. Followed by a court hearing where a judge just looked at the DNA results, ruled him the father, and just put joint custody since we were together and living together. Well now we are splitting. We agree i am taking her back to Texas(I moved here for him) with me. And coming up with our own visitation schedule and amount he is going to send me every month for her instead of going to court and battling. So Do we have to notify them that we are doing this or is it okay to just leave the decisions between us?