Even that can be confusing because it does not say only one wife,
The second option would be if a man was divorced and remarried but since Jesus said that would be adultery I doubt they would be a Church member, much less an elder but only a member of the congregation.
The third option would be if a man lost his wife through death and remarried and I don`t see how that would disqualify him.
Your guess is as good as mine.
Keep in mind there was a provision for divorcing a wife that a man had married when he was a pagan if she left him when he converted. (Actually, that option still exists.) Paul may have intended to exclude such men.
There is also considerable evidence that the ancients were not impressed with a man who was widowed and remarried in mature years. It was viewed as a sign of not being able to control one's appetites.
The "husband of one wife" clause had nothing to do with polygamy, which was equally unknown among Greco-Roman pagans, Jews, and Christians in Paul's day.