Those are hard questions... Here's what I'd say. Feel free to disagree, cuz I'm no expert!
Have you told your parents yet? I'd gently turn this back to her, ask her questions "Is it important to you that I don't? How do you want it handled? How are you handling your parents?"
Do you hate me for still being here while I'm talking to this guy? No. I don't hate you, although I'd prefer this wasn't happening. (don't refer to OM in your answer)
Why do you still love me? I was such a horrible person to you? Because you aren't your actions. (don't say "I love you because..." cuz we aren't saying that we love them)
The shorter your answers, and the more they focus on her needs instead of yours, the more open she will become. You may end up biting your tongue in half!
If she was motivated enough to commit to leaving, she'd be gone. Her presence indicates ambivalence. Tip the scales in your favour by being the more attractive option.
