If you're specifically narrowing the criteria to "who played for the most teams in five 'active' years" as opposed to the more reasonable, "who played for the most teams," I don't know what the record is, but I know that it's not particularly unique: Marcus Thornton, George Hill and Garrett Temple all played for seven teams in a "five active year" span, and all three ended up playing for more teams than Cousins over the course of their respective careers. Isaiah Thomas played for eight teams in a "five active year" span, nine if you count the fact that he played for the gd lakers twice. Dwight Howard also played for seven teams in a "five active year" span, if you count the fact that he, too, played for the lakers twice.
EDIT - Doctor Internet tells me that Chucky Brown played for eight teams in a "five active year" span, as did Anthony Tolliver, and **** Tony Massenburg played for nine teams in a "five active year" span, unless you count the two years he played in Spain against those five "active" years.