Coming in late here...

It sounds as if the problem isn't that you've failed to apologize enough; it's that your partner, for whatever reason, isn't able to accept (or even hear, really) your apologies. She sounds a bit obsessed with keeping you apologizing. I picture it as a ritual that once made her feel a little better. If its "effect" were wearing off by now, she might feel as though she had to get more and more of it -- run faster and faster just to stay in the same place. I think it was Eric Hoffer who said something like, "You can never get enough of what you don't really want."

If she were aware of that on some level, she might even be feeling bad about herself and taking that, too, out on you. I don't know of any way to make her see what's going on. If you can avoid blaming her (or even triggering her into feeling blamed), she might in time feel secure enough to try a quick reality check or three.

If I were in your situation I think one of the first things I'd want to attend to, would be establishing and maintaining "good boundaries". That would include neither blaming her, nor going along with her when she insists on blaming you -- nor blaming yourself and trying to make yourself feel differently. If you found you couldn't seem to maintain good boundaries with her no matter what, you might even decide in time that your relationship was unsustainable.

Good luck!