How can I prevent my texas toast from sticking together?
If you're making it yourself... freeze the slices separately before putting them in a container. Put them in a single layer on a baking sheet, then put the sheet in the freezer. When frozen, seal them tightly in a bag or wrap in plastic wrap. Since they're already frozen, they won't stick together.

(They do similar things commercially with shrimp, fruits, and other things. It's called Individual Quick Freezing.)

If you're having a problem with store-bought bread, you're kinda stuck. You can try defrosting it in the microwave to make it easier to separate the slices. But really, they should have been IQF frozen or otherwise prepared. They may have defrosted and re-frozen, which is a sign of improper handling (either at the store or by you).