Need some advice here.....

[jtrain12]

Alright, so my ex-girlfriend, who i am still friends with, has recently started seeing this guy. I have been sort of skeptical of this guy from the start, as he is 6 years old than she is (shes 18, hes 24). Well last night, when she was drunk, my friend confessed to me that he has been hitting her, in addition to not approving of her hanging out with me, or with girls in her sorority. When I told her that she should leave him, or at least get counseling, she said, "no, its not that big of a deal, because I do stupid things so I deserve it, and hes a nice guy sometimes." She also made me promise not to tell this to any of her friends.
So anyways, im conflicted as to what to do here. On one hand, I know that she will not have the courage to step up her self and take the proper steps to take care of this problem, wether its leaving him, or getting counseling, or calling the police or w/e, and since I now know this is occuring, I feel somewhat responsible, espically if she were to get seriously inured as a result of this. However, on the other hand I don't want to betray her trust on this matter.
P.S. this may seem like an attempt to get back with her/ get back at her, but you have to understand that couldn't be further from the truth; I broke up with her, and she gave me multiple opportunities to come back.