I'd like to move out of state with my son.?

I've met someone and we plan on getting married, and he owns his own business out in Kansas. I have a 5 year old son I have custody of and his father gets visitation. He doesn't exercise the visitation regularly. He is also required to keep insurance on my son, which he has not done. I've paid all medical bills on my own since my son's birth. He's already had his custody lowered once, and he can barely afford to keep himself afloat. He's moved three times in the last couple years. I have a feeling his father will make this a big ugly mess, but regardless, I'd like to move out of state. Do I stand a chance of moving and being able to keep my son?