Being betrayed brings a lot of grief IME. A lot. A whole lot.
My approach was to feel it and let it out in the hope that it would eventually end, and that seems to be happening. At 2 1/2 years out, I still feel grief from the A, but it's not so frequent or heavy that I can tell you how often.
So the bad news is that letting the grief go may take you a long time, but the good news is that it does end.