Witness,
I do hope that you are feeling a bit more together in the light of day - I see your post went up early this morning our time - the night can tend to bring everything home with crushing force at time like this.
First, I have been with my wife for > 20 years now & have had some pretty rough times - we occupied separate parts of the house for a couple of years and went through the "I want a divorce now" scenario more times than I care to remember. In her case it was a "testing" to see if I cared for her as she believed that I did not care. I never at any time fell into that trap despite some pretty solid aggravation as I did care.....
DO you want to stay with her? If so, think really carefully about leaving / finding somewhere to stay as it can escalate the whole mess by a few orders of magnitude.....been there done that.
Are you upset & emotional? Try to think rationally about things & try not to let your strong feelings of impending loss & disaster guide you. Actions taken in these circumstances (like simply walking out) can be disasterous. I don't know your family circumstances (kids etc) but be very aware of AUstralian Law on this point as you can be taken to the cleaners and would strongly suggest that you talk to a solicitor (even on the quiet) so that you know the consequences of your actions. Believe me, I have seen a close relative cleaned out totally as a result of walking out.
She is agressive? I take it that the back injury is serious. I went through a long period with my wife suffering a degenerative spinal condition that was ultimately fixed by some really serious surgery. In the year leading up to the surgery she changed (moody, angry, agressive) and became less tolerant of everything & everybody (this was unrelated to our earlier problems). SHe progressed from Paracetamol / codeine through a spectrum of prescription opiates that made her sick - she suffered from many side effects from the medication. Pain is a powerful enemy and the drugs used to control it can cause so many issues. Kurt Vonnegut wrote "Bad thoughts and bad chemicals are the yin & yang of madness" - never so true.
You wrote "I FEEL TORN IN HALF. I hope I can make it thru this without dying" - I feel for you my friend, I have been there and had those feelings, but do try to think about what you do BEFORE you do it, and if you want to stay with her avoid doing anything preemptive. It will make things harder.
Take care, and keep posting,
h9k