My story, need help before I mess everything up.

[MrBond]

The straight up response to your post above is that it's shown you haven't learned much. Just being honest.

I don't think you realize how much you are trying to control your W and tell her how she should be feeling. It's your lack of being able to control her that's making you feel crazy. Here are the examples:

"main sticking point that I feel is stopping us making progress is about the morning in mid December where I gave her the ultimatum of me or Nick."
"however she said it was nothing to do with the ultimatum."

So she says that it has nothing to do with the ultimatum. Why do you keep insisting your POV is right?

"I demanded her phone of her so I could check for more text,"
"she said "what gives you the right to demand my phone off me or demand anything for that matter?" I replied with there were extenuating circumstances and I've never demanded anything off her before and in a marriage in very rare circumstances it is alright to demand something"

No it's never alright to demand something from another person. That shows insecurity. I think if you would have started building back the trust between you, you could just ask and she would've given you her phone freely. total buzzkill.

"I've said to her previously that I was sorry for shouting at her and I was sorry for making her feel scared and if I could go back I would of handled the situation differently but I was so messed up then in the head I really didn't know what I was doing half the time."

You're still acting like that sorry to say.

"how do I get through this when there is no recognition of the good times, empathy towards me, good will on her part and no attempt at any kind of forgiveness?"

Again you are making it all about you and when do you get something back.

Let's face it, your W left because she felt that she was not having her needs met. So right now you're going to have to deal with that first. Deal with meeting her needs even if it means shutting up for a little bit and listening AND accepting that this is where she is right now. In order for your sitch to change, someone has to change first.

"I apologised before but I can't see (and I really have tried to see) why shes still angry 2 months later"

See? Again, YOU can't see, etc. You're not her. She's still angry for whatever reason. Could be because of you, could be because of her shame, etc. But bottom line is that you don't know.

Try starting off with a fresh mindset. As if she was someone whom you met for the first time. Would you have expectations of how they act? Would you be analyzing every move they make or would you just accept them for the way they are currently? That's the way you've got to start off in order for her to feel safe. She really feels like she's being judged by you. You can argue to the contrary, but it leaks out in your posts. That's where the control issue comes in.