Legal Question in Criminal Law in Texas

I have not researched my response and I would urge you to get a second opinion.

As far as I know, a person with a mental hospitalization may not be able to purchase a firearm, or might have a difficult time in purchasing a firearm.

As far as I know there is no criminal law limiting your ability, or making it a crime for you to have a gun when she is present.

However, if she uses the firearm to harm someone, either accidentally, or on purpose, and the person who is hurt finds out that you knew, or should have known that she had mental health issues, they would probably have a strong civil law suit against you for negligence, based on her actions.