abbusive partner

It hurts so bad that he's abbusive and knows he's sick he always says I'm sick so what ??? Always mentally and phiscally abusing me to use my car we been together for 8 years idk what to do anymore I'm going crazy my depression getting worse I love him but I'm going crazy my self now 
UPDATE : not long ago he got buckets of water I was standing in the corner bleeding from my mouth and he through maybe 20 buckets of water on me and I called my sis on FaceTime to see what he's doin and he acted like he wasn't doing anything like he didn't hurt me at all he put his knees in my arm and kept askin where's the car keys holding my mouth like he's turning so crazy I think he needs to see a therapist or something ASAP ONE MINUTE HES HAPPY NEXT HES CRAZY AND INFRONT OF OTHER PEOPLE HE ACTS SO SO DIFFERNT !! Like nothing wrong with him and acts like I'm the one crazy he really needs mental help idk what's goin on with him