Being a single man, I dance almost exclusively with other men's wives. And, yes, I still find it intimidating approaching the table where the two of them are seated and asking her to dance. But realize that the other man expects that you will dance with his wife.
One thing I have found that helps to "grease the skids", so to speak, is to take part in the free dance lessons that sometimes precedes a dance. And make a conscious effort to NOT partner with your wife during the lesson. Everyone is very casual during the lesson and, in most instances, you can find yourself having danced with numerous partners. Be cordial, get their names and just have fun. Then when the actual evening of dancing gets underway, you will find it easy to seek out these same women and to ask them, by name, for a dance.
As for the conversational tendencies of many women while dancing, I, like you, am not powered solely by muscle memory and must therefore stay somewhat focused on what I am doing. The women seem to understand and will eventually stop talking altogether, equating less talk to a more enjoyable dance. I do hope someday to be able to carry on a conversation while dancing. I'm just not there, yet.
Good luck to you!!