My question involves landlord-tenant law in the State of: Florida

My ex-partner and I own an investment property. The house was purchased with a mortgage in both our names and the deed has both of our names with joing right of survivorship.

Currently the house is rented using a standard florida lease - both our last names are listed as the owner (ie - Smith/James). I handle all the paperwork so the signature line on the lease is only mine, so i am the only one who signed. The 1 year period on the lease is up and the month-to-month provision has kicked in. My partner wants to kick out the tenant so he can move in. He has said the lease is invalid because he did not also sign it too. Is that true?

I dont not want the tenant to move out, he has never had any late payments and he does not want to move.