The question was put: "I am not really sure about this but in order for a man to make it to the highest degree in the celestial kingdom does he have to be practicing polygamy there?"

To which I responded:

In my opnion, the short answer is, "Of course not!"

But the more important question, in my opinion, is not whether God does or does not require it, but rather why he would or wouldn't. I do not believe that God generally commands anyone to marry anyone else. I believe he leaves it up to us to decide. By the same token, I believe God neither commands polygyny, nor does he prohibit it among fully consenting adults. The decision of whom to marry is highly personal and intimate, and in this matter, God can give us a certain amount of inspiration to sense the degree of compatability of a prospective mate, but he does not generally tell us we must or must not marry that person.