1) Better half 2) Joseph Smith was one 3) Married person 4) Mate 5) Partner 6) Spouse 1) Polyandrist 2) Polygynist 
self created photograph by BurmaShaver {PD-self|date=October 2006} ...
• (a.) One who practices polygamy, or maintains its lawfulness.
Po·lyg'a·mist noun [ Confer French polygamiste , polygame , Greek ..., adjective ] One who practices polygamy, or maintains its lawfulness. 
[n] - someone who is married to two or more people at the same time
polygamist Someone who commits polygamy.
noun someone who is married to two or more people at the same time