I am from Nigeria and I know that there are many tribes and people in Benue state. They don’t all have the same culture. The people I am assuming you refer to in this article are the Tiv people and they have denied this practice. They are famous for being hospitable people, and they do not share or offer their wives to house guests. http://pointblanknews.com/pbn/articles-opinions/misconception-tiv-hospitality/

There are several other sources on the internet to prove that it is untrue that visitors can sleep with a Tiv man’s wife. I have #Tiv friends, my husband also lived and worked among the Tiv, and he insists that the Tiv man will 'kill' you if you come near his wife.