Is your girlfriend affected in other way because of her traumatic past? If so, perhaps there's a way for you or someone else to suggest that she get some help to deal with this trauma.
I know this may be hard to bring up. I also understand that the condom issue may be hard to address.
But, my thinking is this: You appear to love this girl. If you think you might want to have a long-term relationship with her ... you need to find a way to help her heal. Otherwise, it's likely to be bad news for you both. That may just mean an unsatisfying sex-life or perhaps an unwanted pregnancy, etc.
BTW, have you always had this issue with girls? Has it always been the same with all your previous girlfriends? Or, is this specific to this girl?