Obviously H doesn't trust you, and certainly he has a basis for not trusting you, such is just one of the consequences of having had an affair. However, when you had that affair, you were looking for it. This business dinner is not about you seeking something outside the relationship. In fact, your mind set now is about making the marriage work. H, tough as it may be for him, has to discern the difference and not attach unrelated "history" to this dinner function that was assigned by your boss.
Realistically, H cannot forever keep you prohibited from evermore doing what you have to do.
His bringing the affair up again and insisting you don't attend is his way of trying to stop what he fears may happen, of course. But honestly, if someone wants to cheat, they find a way, despite all the "rules" and "prohibitions" and "checkpoints" and 'safeguards" the "innocent" spouse may insist on that only serve to lull that spouse into a false sense of security. He has to learn to let the past go if you two indeed are sincere in moving forward.
Comes down to trust. Trust hasn't been rebuilt, and frankly, with things not going smooth between the two of you, there isn't solid ground for trust to grow.
You can offer reassurances, give him the location and itinerary where the dinner takes place, don't deviate from that, and remain fully available by cell phone should he wish to call and check in.
NYS, next time you happen across my thread, I believe it was you that mentioned a book on validation techniques. What was the name of it again?
"I Don't Have To Make Everything Better" by Lundberg & Lundberg.
He mocks anything I do
He mocks the BB
Makes fun of me
makes fun of the books I read
Those are controlling behaviors. Belittle the victim, show contempt by mocking. Roll your eyes, sigh, and scornfully dismiss the victim. Tear away at their self esteem, belittle their efforts; basically tell them that they're 'not good'. The results of it, though, are destructive, aren't they?
These are the things your H has to work on, and that's why joint counseling sessions may be a good venue to reveal these behaviors and unravel them and for him (and you) to learn new ways of interacting.
He says the only reason I do this is to try to get justification for the things I do, but that the only people that respond are going to be the ones that agree with me. So therefore I'm deluded about what people really think... He said that I'm not doing it to change myself, but to get ammunition and support for keeping myself the same.
OK, we don't have to go into all the reasons why H's view is skewed here so as to answer these allegations, you know it's not as he claims it is. All his arguments against it are superficial anyway, they're to discourage you and tear you down. To get embroiled in his arguments is a fool's game.
So, I suppose the above is a good example of what you mean when you ask, "How do I validate BS"?
"I can understand why you'd think that", you could say. "I'm not perfect, and I make a lot of mistakes thinking I may be right. So, what I'm trying to do is learn from the experiences of others, rather than go at this totally alone. Keep in mind that the forum is mostly comprised of the people that didn't have the affairs, people that look to work on saving their relationships, not the other way around, not people who just want justification from others to 'stay the same'. That forum is all about making changes in behavior and seeking beneficial solutions and making relationships work. That's why I want us to go to MC. I'm told it could help us. That's the kind of advice I'm looking for."