Custody of my children, moving to Florida in 2months

Hi, I have a 15yr old daughter and a 2 1/2 yr old son, I'm planning to move to Florida in 2months for a better job opportunity. My x husband says he will fight for both of kids in court for them not to go. I believe I have a better chance in winning in this case because my x husband is to busy leaving my little toddler with his sister to watch while he goes out, & my 15yr doesn't like going over his house because he is alway drunk. I believe that me moving to Florida with my kids is like giving them a fresh start to a new chapter in our book. My daughter has seen how her dad treated me and it's not fear for my daughter to be tainted, an don't want my 2 1/2 to grow up thinking it's ok to treat women that way. I already have a place to stay and a good job waiting for me. Please help on any input. Thank you.