'Benjamin Button' Star Madisen Beaty -- My Ex-BF Crossed the Line in Bed ... and Abused My Dog

Actress Madisen Beaty says she fears for her life after her violent ex-boyfriend beat her up during rough sex and terrorized her dog.

Beaty -- who stars on "The Fosters" and also appeared in "The Curious Case of Benjamin Button" -- got a restraining order against ex-bf Cameron Brown. In court docs, she says Brown severely abused her and damaged her stuff by:

-- repeatedly punching her in the face during rough sex
-- choking her with a seat belt
-- throwing a broken cabinet door at her
-- tossing her cell phone "down the block"

Madisen also says in the docs ... Brown threw her white standard poodle named Beverly around her apartment -- and drove recklessly while Beverly was unsecured in a backseat. She says the pooch got tossed around the vehicle.

If that wasn't bad enough, Madisen says Brown repeatedly called her an "overdramatic actress" who "cried way too easily" and that he "enjoyed" hitting her in the face.

The judge ordered Brown to stay 100 yards away from Madisen and her poodle.