The reality of a Polygamous household means a fair amount of effort, and that's even with a harem that all get along very well. In fantasy play, go for it, the realms of fantasy are just that, right?
If you step into the Reality of a Polygamous household, be careful and make sure you select those who will get along and bond well. I got very damned lucky with the situation that unfoled of it's own accord here in my home--6 women--and not a day happens that I am not very glad that they all get along and have a 'sisterly' sense of things happening.
NOT a thing to take for granted.