I am surprised at how brutal some people can be on here- not convinced they'd all be so carefree IRL.
Your husband should absolutely go to the meal- ridiculous over-reaction to say that he shouldn't, and unnecessarily escalates the issue. He's done nothing wrong and shouldn't be cut off from his friendship group.
Best way forward would be to send her an apology- something along the lines of "I've just heard that I really upset you at the wedding and I'm so sorry, I had no idea and it was never my intention, by my silly comment I simply meant bla bla bla, I'm mortified that you were so upset and I was oblivious to it! Hope that clears things up- it really was a silly miscommunication and I should have been more sensitive"
That way you have the moral high ground, you have shown a nice kind side of yourself that they have yet to see, and you've just done a nice thing (don't quite understand why so many MNetters have such difficulty being nice when it's no skin off their nose).
Sadly, whilst I'm sure you really are lovely, you've gone into an established friend group, upset one of them and given them plenty of fuel for thinking that you're just a bit of a bitch. Until you're really sure of the dynamics, sense of humour etc. it's always safest to errr on the side of caution!
If it were me I'd also send a message to the bride saying something along the lines of 'I'm sorry to hear of the impression you had of me as I don't think it represents me well at all- I've sent a message to [friend] and tried to make amends, but if there's anything else I can do please let me know as I'd hate to think you all think of me as someone I'm not"
Keep it all light, non-accusatory, friendly etc- I'm sure you can be more articulate as I'm shattered tonight!
Motto for life: Be the better person, moral high ground, etc etc 