Some states will stay the entry of a divorce judgment, or will reserve the issue of nonpaternity, support and custody, until after the child is born and DNA testing can be administered. I don't see a prohibition on a grant of divorce during pregnancy under Florida's statutes or court rules, but even assuming there is no law, as a practical matter some courts may choose not enter the divorce judgment until paternity issues are resolved through genetic testing.

If you can't serve your husband by conventional means, petition the court to allow substituted service.

You can raise the issue of pregnancy and nonpaternity in your divorce complaint. From what you say, you want the judge to rule on the issue of nonpaternity. You may not use Florida's simplified dissolution procedure if you are pregnant.