I'm worrying about the OP too. I've seen that look. Those bulging eyes like they are about to pop out of the head. My brother in law had this and he threatened to kill me. This man is harboring anger to the point of rage. The man really is crazy even if he can't admit it to himself. There are some medical conditions which can cause this such as tumor.
If you insist on staying in the relationship you could try improving the environment you live in so it is more uplifting mood. More light, fresh air, scented candles and good music. You could also adjust his diet to be more calming foods. Hell if you gotta slip a tranquilizer into his food you gota do what you gota do.
Either way have to call the police and file a report just for record sake. I filed a report on my brother in law when it happened. When he went to get another job they did a background check and he was denied though.