Sorry to hear about the problem! So many "ex" issues...
The easiest thing might be to tell him that you're going to go to the police and report a theft of personal property -- the potential for criminal charges for trespass and theft/larceny. There might be a potential identity theft issue here as well and you may want to change all your private numbers as well, especially financial issues. I'd say that warning him may be the best way to get the desired effects.
Florida apparently does have an "Invasion of Privacy" statute which may apply here although it does have requirements. There are four kinds of violations:
1. intrusion upon a person's seclusion or solitude;
2. appropriation of a person's name or likeness;
3. public disclosures of embarrassing private facts; and
4. publicity which places a person in a false light.
Here is a great article from the
Florida Bar Association web site. It gives you a complete understanding of this law including history -- in short, this cause of action is a recent creation in American law, dealing with the repercussions of all kinds of "surveillance" technology that has sprung forth in recent decades. In essence, there is a 2 step process to determine liability:
"First, has the tort been committed -- that is, has the newsgathering or publishing process violated certain legal principles which protect the individual?
Second, even if there is a technical invasion of privacy, is the press "privileged" under the First Amendment? Just as in libel cases, there may be a sort of "constitutional excuse" granting immunity for some articles or broadcasts which otherwise might lead to damage awards."
That should get you started. But honestly, if you have any relationship with the ex-B which it seems you do, perhaps it's best to explain to him that you know your rights and if it doesn't stop you will have no choice but to go for the jugular and he
will lose. He stole your private property and his postings expose him to liability for him under Florida law. Dazzle him with your knowledge.

Good luck.