Ex Is Refusing To Pay Rent

Location: Cincinnati, OH
Ex’s Location: Dallas, TX but is staying on a friend’s couch at the moment. Not sure if that’s super relevant but I wanted to provide it just in case.

I broke up with my ex about a month ago, on July 30, after finding out he had cheated on me a few weeks prior. In that conversation (recorded), he assured me that he would try pay rent for as long as he could, to which I responded and said “No. You will.” Nothing further was said about it in that conversation. On August 1, we had a more in depth conversation (again, recorded) where he agreed to pay rent until I was able to find a roommate to cover his half of the rent, or until I was able to get out of our current lease. As assurance that he would uphold his side of the deal, he sent me September’s rent on that day. That evening he moved back to Dallas and has been couch surfing since.

This morning, I texted him and asked if he’d be able to pay November’s rent, to which he responded, “To be honest, it’s not looking good.” My mother is listed as a guarantor on our lease, but it’s not fair to have her cover for his half of the rent if I’m not able to. Is there anything I can do legally if the time comes and he refuses to pay rent? Some friends have suggested small claims, but would that do anything if he doesn’t have the money to pay? How would I even go about that? Please help ????

Edit for clarity: My ex is also on the lease, along with myself and my mother.