So, not to belabor the point (but I'm very nervous), even though my ex was the original tenant and put down the security, I cannot legally be evicted as long as I continue to pay half the rent?

I need to go out of town for a few days (job interview) and frankly, I don't trust what she might do while I'm away. I'm fearful that I may come home to find the locks changed and my stuff on the street!