Cacotopia
Let's go full Trottle
she knows it's a hollow threat. I just couldn't see any rational method to get her to take her head out of the sand. it's apologized for though.My advice is to apologize for threatening to abandon her. Ultimatums are a power play. You essentially threatened to deprive her of emotional security if she did not bend to your will. The intent behind this action is to create an anxiety within her that forces her to act according to your will.
If you would truly contemplate terminating your relationship because she did not seek help then perhaps you should just terminate the relationship and not attempt emotional manipulation of a victim of sexual assault. If doing so is the only way to preserve your sanity, then that is justification enough.
If however you are willing to suffer the emotional turmoil of seeing a loved one suffer in order to provide a respite then continue to engage her and offer advice on how to ameliorate the situation.
It is hard to know whether or not she going to the authorities would help notwithstanding her belief to the contrary. If she chooses not to contact the authorities, perhaps she at least has trusted friends she can ask to accompany her or with whom she can stay, until she can move to a different residence.
If I didn't care I wouldn't be going to the lengths I am going right now to see that she gets help.