Ok, I am coming from an angle a little different, in that another disorder may be at play as well. I am dual diagnosed. I am bipolar with hyper mania as well as suffering from PTSD. While no causal link has been identified with sexual indiscretion and PTSD. It is exceptionally common with Bipolar disorder, when in the manic state. That said, I am not saying it is ok, but is it possible she has another disorder that has not come to light. Whether you choose to stay or go, have her talk to her psychiatrist, not a counselor. A medical doctor, this may be a symptom of something else. The fact is that what she should be doing is having safe intimate activities that build trust between you and her, and that work to change her feelings about sex. If we let our disease be an excuse for bad behavior, then the disease wins.