Help Please and Hurry

I have had my son in my care for over a year now and he went for a visit. There has been no custody order and we where never married. He is 3 years old and now she does not want to let him return.

She is however, letting him return for a visit only and we live in 2 diff states.

He has been in Florida visiting for 2 months now and will return in two weeks for a month visit. I do not want to let him return? I need advice and I need it fast please help. Thank you in advance for your time and help.