seven
King David had eight wives and at least ten concubines. His wives are listed in 2 Samuel 3:2-5, but the list is missing two wives - the first one, Michal, and the last one, Bathsheba. Their names in order are:
Michal
Ahinoam
Abigail
Maacah
Haggith
Abital
Eglah
Bathsheba
2 Samuel 5:13-15 says that David took more wives and concubines in Jerusalem, but doesn't list how many, only names the sons born to him there. In a later passage, we are told of ten concubines whom his son Absalom defiled, so at the very least, David had eight wives and ten concubines - probably more.