Can my ex-husband modify custody to live with children full-time?

Question Details: My ex-husband lives in one state and I live in another with our 2 children (4 and 6). He is planning to move to here and modify the custody so that he can live with our children full-time. He wants to do this because he believes that my re-marriage will negatively affect the children. My children is very attached to my fiance and my ex is afraid that his role as a father will be taken away from him. My ex was physically and verbally abusive during the marriage, and he is still harrasing me with threatening e-mails, saying that he will get full physical custody of children. Important Notice