No, I would never consider a polygamous relationship. I believe such a relationship to be toxic and confusing, especially if there are children involved.
The polygamous relationship to me is just as bad as the open relationship. It could be fine to a point, then it will start becoming complicated, especially if this other person and her family become part of your home or community. Take a look at this article to assist you with this choice.
The most important thing, however, is to figure out what each party wants or like before you get married. Do not wait until after the marriage to tell your spouse you want a polygamous relationship! Go to GoMarry.com to find the means to ask the difficult questions before the wedding day!
