Frustrated and in need of advice

Hello , little background me and my boyfriend met 3 years ago and just recently got married last month . Well he has a child with a previous partner and she is ... something else . When we first started dating she didn’t let him see their daughter at all because he was with me , he was paying her 400 a month willingly even without seeing his daughter, she then came around a little and started letting him see her , he’s still paying her 400 dollars a month no child support no nothing , she complains because she feels it’s not enough , recently my husband came down with the flu and missed a few days from work so his paycheck wasn’t that great , so instead of 400 he paid her about 330 . She was livid , and threatens that she’s going to get the best lawyer in Florida so she can get everything out out of him. She dangles Their poor baby girl in his face , My husband cries because he just wants to be in his daughters life , people tell him to put himself on child support but he’s heard horrible stories about child support from other men so he’s scared . He doesn’t know what to do at this point. We have a home and pay bills equally , I pay more sometimes because of him having to pay her . So we are stuck ... anyone know how child support works in Florida ? Or what should he do ? Help please