I'm struggling and just need some understanding

[Inertia]

Oh, i can relate with the mad bit. The good thing about that is it gives me a little insight (finally after world wars 3 through 33).

When I try and discuss my feeling that are being caused by a decision made that was primarily his, a wall used to go up with him. This massive defensive wall and all hell broke loose. As quiet as possible for 3am. I get insomnia when I stress and breakdown when I become too tired, which wakes him up and then HE asks whats wrong, and gets defensive when I tell him. It was utterly frustrating because it was a never ending cycle.

The reason he got like that: It hurt him to be told his decision was hurting me, and he was protecting himself from that guilt.

You need to diffuse all guilt before any meaningful conversation can take place. I hope this helps you because it took us 5 years to realise why this cycle kept going. Its because I never felt it was resolved, and he felt it was because it kept him protected from the grief I felt which he felt responsible for.

[Smoke Jaguar]

You need to diffuse all guilt before any meaningful conversation can take place.

I think that's critical! Guilt in a person so often manifests as anger, because they resent feeling guilty and culpable...when an open conversation would dissipate a lot of that feeling of culpability!
Understanding that it's not their 'fault' is probably a huge stepping stone here, but worth the effort of getting to that point.
Excellent point, Mags