It doesnt stop

She has been out of town for a little over a week. and she will be gone for another 5 days. It seems like we have argued everyday that she has been gone.
We stayed up till 4am arguing on the phone last night. To the point where she was talking about separation. I tell her to make a decision. She says she cant right now. By 4am she is saying she doesnt want to be separated she just thought that would be good for me (she broke my nose and choked me about 6 months ago and I just havent been the same since) and that maybe we would be better off missing each other. Shoot, she will have been gone for 2 weeks... its gotten worse.
Today we were being normal... until we were talking about something we didnt agree about. She starts attacking me (she said she was joking) and I got pissed and yelled at her. That was that and I dropped it and started talking about something else. I didnt want to have a repeat of last night. So she answers my questions about some pistures and then says "I didnt appreciate you responding to me" so I said " I didnt appreciate you attacking me, especially about a subject you already know Im uncomfortable with". 
Its like she fees like she should be able to say and do certain things but I shouldnt. Like she cant admit she could be wrong. Im not saying I responded the right way... but this is something that has BEEN going on. I have been struggling through her cheating on me more than once and being physically abusive with me.
Im really struggling getting over it all... I feel so overwhelmed.
I think its even more difficult to get over things when she acts like Im making a big deal out of having my nose broken by her.
She says things like "thigs like that just happen in relationships"
I dont know... the arguing never stops. Im supposed to change the way I react to what she says and does... but she hasnt tried to change what she says and does.