I’m very glad to hear that most of the time things are “amazing” between you. I hope the “amazing” and the fact that you have two children who need you motivates you both to fix this. You made an important step in writing to us here at PsychCentral.
You seem locked in a cycle of blaming each other. Assigning blame isn’t at all helpful. Even if you could decide which of you is more guilty, you would still have the communication problems. I have a guess that there is something you two aren’t talking about that is so difficult that it seems better to fight about “communication.” From my point of view you are communicating perfectly. You are communicating that you don’t want to communicate.
A couples counselor will be able to observe the two of you in action and will be able to help you understand why having the block is more important than not having it at this point in your relationship. You can then work on the underlying issues and become a stronger team.
I hope you will follow through.
I wish you well.