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He can't have it both ways, you either abandoned the house or you pay rent. As long as you are paying rent then the right to use the property is yours and, unless there is something really unusual about your written lease agreement, he can't just come in your hose and do those kind of things.
Your only real option is to sue him, but if he is agreeing to let you out of the lease you probably don't want to do that since he can change his mind. In the case of a lease for real property (real state, house, etc) it is only enforceable if it is in writing, or at least that's the way most judges will interpret it due to a concept of law called the "Statute of Frauds" (which really has nothing to do with fraud.
If you do choose to pursue him then you could sue him in small claims court which, in Texas, is the Justice of the Peace courts. However, the burden of proving your damages is on you and it would be difficult to prove how much he cost you in extra utility bills.
If you decide to sue you can also use a lawyer and since it is a breach of contract action then you can sue for your attorney's fees as well.