(Disclaimer for other mumsnetters - this is a response to the OP's question and not an invite for the masses to respond to me, twist my words and put me down. I have answered the OP's question from my own personal opinion. Please only do the same if you feel the need to respond, lol). For what it's worth...
Well well well, OP,
I'm wondering if you regret posting your question on here not, lol? Did you get the response your were hoping for? After all, people mostly post on here seeking validation of their own viewpoint, as opposed to putting in their subsequent lost time working on the issue with the relevant person. How much time exactly has been spent reading all of the responses and formulating further responses yourself? Who knows...
I love reading MN posts as it is a fascinating insight into human behaviour, values and principles. As usual, the OP receives several hundred perspectives based on the life experiences and values of other people, none of whom are living the OP's life, therefore throwing the actual dynamics and true context out of the window.
OP, there are many, many valid points posted on here in response to your question, some with extremely adept articulation, and others with the comprehension of a monkey holding an iPad and being asked to back it up to a PC. I enjoyed wasting 30-45 minutes reading some selected answers and typing up my response, which I do agree is far too long, lol. Apologies.
Your husband sounds like a great partner and your relationship has been presented as robust, but, we are all emotional beings at the end of the day and we simply cannot help the way we feel in any given situation.
In my humble opinion, you should simply respect your husbands feelings and decline the invitation. You have asked him and he has given you his answer. It seems you posted on here to attain validation for going out with another man as you would like to enjoy this nice meal and you have come up with every reason imaginable to justify why you should attend the experience. HOWEVER... you are repeatedly dismissing your husbands feelings and are trying to overcome his objection from every perceivable angle. He sounds a reasonable man who simply is not comfortable with his wife having a posh meal in a romantic setting with another man who may possibly be on the rebound.
Rather then post on here and spending eternity reading hundreds of posts and posting reply after reply, your time would have been better spent discussing your husbands feelings with him and ultimately respecting his viewpoint.
If your DH was comfortable with the scenario, then fine, but the reality is, he is not. If you eventually do manage to twist his arm into agreeing you should go for the meal (perhaps you would show him that 68% of musnetters agree with you, not sure?), there will still be a part of him that is resentful and your relationship may have been negatively affected, even if only ever so slightly. As husband and wife in a stable and balanced relationship, you both should absolutely respect one anothers feelings, no matter what the scenario is that arises.
Obviously, this is purely my own humble opinion as an outsider looking in, like all the other responses, and I am sorry I do not agree with your viewpoint, but please do also consider my response when choosing how you will proceed. In answer to your question, I think YABU in this situation, as your husband has given you his answer and he simply is not comfortable with the situation. He is an emotional being, bless him, as we all are.