Since you're living in Texas, you'll probably have better access to the local medical care you need if you buy a plan on the Texas exchange. In addition, a number of state exchanges offer multi-state plans with national networks of doctors and hospitals. That may be an option if you want access to providers in both states.
To be eligible for coverage on a state marketplace, you have to be a resident there. But marketplaces are generally being pretty lenient about requiring proof. They may ask for a lease agreement or utility bill so it is important to make sure you can provide a proof of residence to be on the safe side.
They may also ask for documentation that your husband is enrolled at the college.