Your best option is to pursue a partition action and force the sale of the property. That is provided that your name is on the title. You should at least seek a consultation with a real estate attorney. That will help you decide if you can afford to sue this man. The fees charged by attorneys vary greatly so consult a few attorneys.
Sadly, this isn't the first story of an ex-NFL player that swindled someone to take a mortgage out on a piece of property.
The Legal Services Corporation can help you find non-profit legal services organization nationwide.
Most Legal Services Corporation affiliates are experienced in these matters. Even if they can't qualify you for their assistance, they may be able to refer you to a firm that will take on this kind of case on contingency. I have received some very good pleadings from Legal Services of Greater Miami, Inc. that allowed me to take on cases that I would not have taken if I had to start from scractch.
However, do remember, you created this problem. You allowed yourself to be invovled with this person in hopes of some benefit personally, romantically, financially or intrinsically. If you play the "you gotta help" role, it will often get you put to the bottom of the list. Be humble as you are asking for assistance. LSC has lots of clients that are outright victims of strangers. Those cases are of higher priority over cases where someone intentionally placed themselves in a relationship with the aggressor.
Check with the Hillsborough County Bar Association and the Florida Bar. I believe both have a low cost attorneys referral service so you can at least get a consult. There are a lot of facts that need to be explored.