If the ex-spouse no longer has title or a valid rental agreement, you can post notice, then file suit. It is easy, but not simple (meaning these proceedings are very technical), so you should hire an atty.
Can an unlawful detainer be used to have a non-spouse who refuses to move out of your home evicted? And if so, how do we go about filing that and what is the procedure? Also is an attornney needed to file this? We are in Texas