Polygamy
To dream of polygamy may be a sign that you don't feel as important as someone else in relationship or commitment. Giving your all to someone who doesn't feel that giving their all to you is necessary. A sign that you need to demand more respect or start setting boundaries.
If you are the polygamist in the dream who is married to multiple partners it may be a sign that you feel more important than other people in a relationship or commitment. Positively, it may reflect your superiority or heightened sense of responsibility. Negatively, it may be a sign that are not returning the loyalty or respect that other people are giving you.
Alternatively, multiple marriage partners may simply reflect multiple areas of your life or habits that you are emotionally "married to" at the same time. Different behaviors or coping mechanisms that are very helpful to you. Negatively, it may be a sign that you feel stuck with a number of different problems.