Well you said Sheba that one of these friends was involved in "this mess", so it seemed likely that he at least, knew. From what you've said about your female friends' reactions, they have described you as a "saint" which is usually diplomatic shorthand for the observation that they wouldn't tolerate these sort of male, cockwaving benders.
You also said you'd read NJF, but am I right in thinking that your H hasn't?
Why is that?
What has he actually done to understand his infidelity Sheba? I remember your story and it seems that for about 6 months, life more or less carried on as normal for him - he refused to talk to you about the affair and was ambivalent about committing to his marriage. Do you have any actual physical evidence that he hasn't kept in touch with the OW? She still works with him, doesn't she?
I think the word you've used yourself is really significant - respect. His actions have shown the opposite of that and it seems he makes empty promises, that he has no intention of keeping.
When you say "What can I do?" that implies you feel you've got no choices. If he also thinks you've got no choices, then where's the incentive to change? Do you think he knows that when it comes to it, you will back down again and not leave him?
I feel wretched for you, because you have been so badly hurt and you seem to have kept this marriage afloat virtually single-handed. I cannot imagine how you got through all those months burying the thing that had caused you so much pain, bit was off-limits for discussion because he couldn't cope with it (and yes I know there was a bereavement, but I think he hid behind that...a lot).
You really do have some choices going forward and he needs to believe that you will exercise them. Please don't settle for this - you and your DCs are worth so much more than this and as you know, if the behaviour that permitted his infidelity is still there and his values haven't really changed, then this will happen again.