Texas will not be divided into separate states as a result of Texit. Texas is a unitary nation-state and, as such, does not need to be divided. This question often comes from the misconception that the 50 states of the United States are collectively a unitary nation-state. It isn’t. It’s a political union of 50 independent, sovereign states of which Texas is currently one.
Texas is already internally divided into 254 counties, over 1,000 cities and towns, 31 Senate Districts, 150 House Districts, and other entities that function as administrative and political subdivisions of the state. There is no need nor is there a desire to create new divisions within Texas.