So, this other incident...
Summer of 2009 was a bad time for our relationship. My dad died in November of 2008. She got raped by an acquaintance in spring of 2009 but didn't tell me about it for a couple of years. She did tell the guy that she was cheating with back then. Then her cat died in June of 2009 and her car totally broke down in early July. She was working a part-time job and my full-time job was struggling to cover my regular expenses, some of her expenses, plus a debt management plan related to large amount of credit card debt I ran up in 2004 while she recovered from surgery related to a car accident.
So we were sharing my car for a while, and it was frustrating because she is always running behind schedule. So she was driving, racing to meet up with a friend who was giving her a ride so I could use the car that afternoon, and we were having an argument about something. No big deal, except that she was becoming very distracted by the argument while driving, spending too much time looking at me instead of the road. I told her to keep her eyes on the road and she told me off. In hindsight, it was reckless, but I reached over and put a hand on the steering wheel and said "let's pull over and switch drivers." That startled her into slowing down a lot, so I turned the wheel slightly and we pulled up at the curb. I snatched the keys out of the ignition, but not before she left a set of scratches going all the way from my elbow to my wrist.
Those scratches weren't so shallow, so there was a fair amount of blood. She was really sorry about that, and admitted that she got out of hand.
I know that it sounds like we're a terrible couple, but there are just these two incidents out of a nine-year relationship, and I don't have any prior history of abuse.