How to help her with insecurity?

From what you have written it sounds like you have taken every opportunity to try and sort out issues within your relationship. You seem very aware, especially with list of behaviours from your fiancee around certain situations.

I just get a sense that she is very anxious and suffers from high anxiety trying to keep everything under control.

You mention that there is a consistent cycle. Sorry, you haven't mentioned your ages, but have you noticed if its around her "time of the month?" (I haven't read your other questions, so just going on the info on this particular one)

You are doing so many right things and especially with counselling for couples too.

My personal experience when I have suffered from high anxiety, I used to "shutdown" and go to bed and not want to talk about things, so really it was a way of avoiding reality.

You come across as a very caring responsible person, so don't neglect your own needs too within this relationship.

You mention that you want to have help with any behaviors or words you can use/practice to help her with this constant irritability/anger!!!

Don't try to tell her how to fix things, as a woman, generally we want to just be listened to and not told how to fix things. I am only generalizing by the way.

Perhaps have some kind of contact with her when she is talking to you, like holding hands and eye contact. Sometimes repeating something you have heard back to her in a different way will tell her that you have understood what she is saying.

Don't challenge her with her behavior at the moment as it may escalate her irritability or anger.

I don't actually know your circumstances only from what you have written above, so these are only suggestions from my own point of view.

Wishing you well in your future counselling.

wow your girl sounds like me and you can't fix what you don't know is broken. She knows whats wrong but it doesn't make sense when it comes out so she keeps it to her self. There can be so many things to blame usually from the past. Well i've learned through listening and teachings i can't redo the past so focus on me. Only i can make me happy. You can't fix her she has to began to see things differently i did. My insecurity came from my dad never coming back to being the butt of dark skinned jokes. You say she's pretty but does she know she is pretty i didn't until i was like 30 i'll be 31 in june. In much ridicule and let downs from people did this to me. Now at this point she has to learn to not let emotions rule her you might want to find a good teaching church and not a religous one. Something like joel olste