I tend to think that Henry believed the charges against Anne in the beginning..at least to some degree.. and allowed himself to be carried away by the whole mess.

That was a different time and by our standards, religious fanaticism and paranoia of the unknown (i.e. witchcraft) ran rampant. Imagine the negative conjecture constantly being whispered about Anne in those days, which surely the king was privy to some of. How many years of rumors must he have brushed off before some of the propaganda finally wore on him?
Perhaps much like the Catherine Howard situation,  intel was brought to him about the queen which at first he was not inclined to believe but ordered that it be looked further into… and that was when “trusted”advisers used the opportunity to smear her.

In the years following.. after the fervor of speculation died down..what if Henry began to suspect that his fears had been played upon by Cromwell, via the charges against his former wife.
I can't help but wonder if the blunder of the Cleves marriage didn't have an almost subconscious stirring up of the mess with Ann B,…. triggering resentful suspicions that all along Cromwell was meddling in Henry's personal life to further his own agenda. After all, it wasn't as if Cromwell had the power to *force* Henry to marry her, ultimately it was his own choice. I guess what I'm trying to say is that Henry seemed to have a rather extreme reaction towards Cromwell over A.O.C.
If he felt he had received poor council, at any time he could have just stripped his power and banished him.

H8 in some ways strikes me as having a child like aversion to anyone he came to believe was attempting to manipulate his life or pulling strings to control him. I also think he had deep issues with betrayal. Many people over the years certainly fell out of favor w/ the king, but surely not all of them died. It seems that many of those who knew Henry on a very personal level and did die, shared a common thread. Betrayal, or an imagined one.