Daughter's father is refusing to help me financially

Me and my daughter's father broke up because of his cheating. I went to move back to my home state up north so I can be by family. He is actually getting transfered to Puerto Rico by his job. Every time I ask for help he says no because he doesn't have his daughter near him. I hardly have any money and he says well just give her to me then if you can't afford to take care of her. He threatening me with custody if I get child support. We were never married. He is on her birth certificate though. I've been a SAHM for the longest time I do get some money coming in. But he has about 55 grand in his checking account and still is refusing to help me. I haven't lived in my homestate long enough to file because I just moved here. Her state where she lived was FL. I've done everything for my daughter. He didn't even take her to any appointments or nothing. Didn't even meet her pediatrician. He was always working and coming home late 8:30pm. He works for the post office.