I'm sure it would be special for Bill Clinton, he would probibly be First Duuuuuuude yet the one who follows after would be the First Gentleman XD
There may not be a term until much later. The term First Lady wasn't coined until 1887. So there may not be such a title for the husband until much later. But people, being the **** that they are, are probably going to try to think of some gay ass title.