This is an old thread, but I wanted to add my thoughts.
First of all, hearing voices in one's head can definitely be sign of schizoid tendencies, especially if they are frequent and insistent, and paranoic. So, get that checked out by a doctor, a specialist, if necessary.
Secondly, in this day and age, where there are more agnostics and atheists than ever, and more Western people interested in non-Abrahamic religions, forms of neo-Paganism or Heathenism, and more people informed about the science of psychology, there are different ways to view the voice of "god."
If we want to call it "god," which god do we mean? We do not necessarily assume it is Yahweh of the Hebrew or Greek scriptures (aka the Bible). It could be Hera, Zeus, Odin, Bride/Bridget, Isis, Asherah, ad infinitum. If you're open to it at all, the right god for you will appear. Do some research. Gods can be very specific in what they offer.
As an agnostic Pagan myself, I can identify the voices I have rarely heard when in a receptive state as Buddha and also the Great Mother. That's just how they appeared in my mind, based on what they said, and when.
Or, conversely, these voices and their words can be identified as deep callings from within one's own psyche. I think that's the best way to define it. But sometime anthropomorphizing this voice as coming from a god/goddess who is outside us, above us, and also deep within us, can help us to get the message more clearly.
The issue is, sometimes if we are off-kilter, or indeed mentally ill, these voices may tell us something that we think must be good, since it seems to come from a higher power, when in fact, the message is extremely harmful, telling us to do things that are bad for us, or worse, bad for others around us. If you're mentally ill, you might think the voices come from a god, or a demon, but either way, you might feel powerless against doing what they advise!
I wonder what happened to this OP! Being told by a god to be "polygamous" is a new one on me. I've rarely seen anyone come here with this problem, literally begging for help. Sadly, this board was new when she asked her question, and there were few members, and few people responded.
Has anyone here ever heard the voice of "god"?
More specifically, has a god (or gods) ever told anyone here that this god (or gods) wants them to be polyamorous?