Any relationship worth having takes work, adjustment, and open communication. We all have routines, whether we are aware of them or not. When our routines get disturbed, it is sometimes uncomfortable.
I think I may be more like your girlfriend--I need to process before I can talk things out. It may seem like shutting down from your perspective, but some people (like myself) need to question their own thoughts and feelings before they can be communicated. I may be angry, but I may not know why I am angry and need time to figure it out. I guess the question is, does she eventually talk it out, or are issues never discussed?
Open communication is very important, but understanding everyone's need to process is key as well. Mona can articulate herself well in the moment. She is very in tune with her feelings. I need to find the root of my emotions before I can verbalize them, or it comes out a muddled mess.
Relationships sure can be a rollercoaster ride!