That Florida address is InmateAid's corporate address, and it appearing on your letter instead of your Tennessee address is by design, not an error.
Privacy protection is one of the core features of the service. When InmateAid sends a letter on your behalf, your personal address never appears on the envelope. The return address is InmateAid's Florida location, which means anyone handling that envelope at the facility, including staff and other inmates, sees only the company's address. Your actual location stays completely private.
InmateAid never collects your home address for outgoing mail precisely because the service is built around keeping that information off envelopes going into correctional facilities. Many people use the service specifically because they do not want their home address visible on mail passing through a prison or jail mailroom.
If you want your boyfriend to have your Tennessee address so he can write back to you directly rather than through InmateAid's response system, simply include it inside the letter itself. That way you are making a deliberate choice to share your address with him directly rather than having it printed on the outside of an envelope.
If you prefer to keep your address private and still receive his replies, he can write back to InmateAid's Florida address. InmateAid scans incoming letters into your account and notifies you when one arrives, so the communication flows both ways without your home address ever entering the picture.