Gosh, that's rough - all those people being two-faced to you! :(
But look at it another way - yes they were dishonest for not telling you what they knew, but perhaps they didn't think it was their place to tell you (often an issue brought up here "I know my friend's H is cheating, should I tell her?" and the answer is usually evenly split between "yes" and "no" because quite often the messenger is "shot" for bringing the unwelcome news).
If they were decent people though, they would have felt sorry for you, being married to an unfaithful arsehole - and now they have a chance to make up for their dishonesty and cowardice beforehand.
Or they could just be hypocrites, as you said.
However, this does give you a bit of an opportunity - you can't rant at your dead H, but you can talk to some of these fence-sitter friends and tell them how hurt you are at their betrayal, give them a chance to explain (and if you don't like their explanation, bin 'em off) - you can take out some of your frustrations on them. True friends will understand and let you do this; hypocrites will run.
Have you considered/had any counselling? I think it might be beneficial to you, not for the grief as such, but to help you with the inevitable trust issues you're going to be dealing with after all this.