First, I am not a Catholic, second, the Catholic Church takes a dim view of spousal abuse, third, God is not in favour of it either...
Ultimately for any Christian (or non Christian for that matter) that is suffering abuse from a spouse, feel assured that an all knowing, all seeing and all powerful God knows your heart and your mind. Getting out of a situation like that is definately in His will. He doesn't want to see you hurt.
As for the vows...they are broken the moment that a spouse hits. A promise to love doesn't say "I promise to love except when I hit"...hitting someone shows decidedly the lack of true marital love and respect...so if anyone is to blame for abandoning the marital vows FIRST, it would be the spouse that hits. Take that back to the religious people who try to force you back into an abusive marriage and remind them that the vows were already thrown aside...but not by you.