My roommate threatens and harasses me. I'm stuck in a lease with him for the next 10 months. What can I do. He's a psycho, and I can't afford the fee to get out.

For example, he lost his temper over me bringing up that he turns the temp down too low at night and it wastes money. He didn't use to be like this, his GF comes over to the house and tries to control me and the other roommate, if we talk back he flips out.