Can child support be reduced in Florida if I remarry and have more children with my new wife?

Children born after the child for which child support is being paid are an irrelevant factor. They are not considered by the court when determining child support for that earlier born child. Now, if you have children from a prior marriage or union that are older than the child for which child support is being considered, that is a factor to be considered, and their child support is, in general, taken out of your income before your income is put into the child support formula for the new child, but that does not apply for after-born children.