You erred in talking to your mom and making your husband the bad guy. Your husband may disapprove of a "destination" wedding, particularly considering that the previous Las Vegas wedding was not attended by either one of you. He may be keeping the peace by not talking about it. Sometimes when you are really angry, waiting is the best option. You might make things worse by pushing him to talk before he is ready. Sometimes people bite their tongues to keep from saying things they would later regret. From my perspective your story goes something like this: You and hubby agree to not attend the wedding, you send your regrets to your brother, bro complains to mom, mom complains to you, you complain to mom and you crumple like a wet tissue, after having made a decission with your husband.
Your mom is also putting you in a bad position. Good parents and in-laws do make their children decide between "family" and partner. All this does is build resentment with people you intend to be related to for the rest of your lives.
Weddings make people crazy. Maybe if you cannot attend the wedding you can plan a special visit with your family and your brother's new wife. Something where you, your husband and your kids have special time with your brother and his bride. Make a wedding gift of an invitation to something you can do together.
Your mom is also putting you in a bad position. Good parents and in-laws do make their children decide between "family" and partner. All this does is build resentment with people you intend to be related to for the rest of your lives.
Weddings make people crazy. Maybe if you cannot attend the wedding you can plan a special visit with your family and your brother's new wife. Something where you, your husband and your kids have special time with your brother and his bride. Make a wedding gift of an invitation to something you can do together.