Marriage in the temple between one man and one woman is considered a celestial marriage.
When the priesthood ban was lifted, McKonkie said something along the lines that members were to disregard everything that had been said previously, because our leaders had seen through a glass darkly. In other words, they didn't get it quite right. I think the doctrine of Celestial Marriage is another example of that type of 'seeing', and I'd think a lot higher of our leaders if they'd just own up to the fact that our leaders in the past saw Celestial Marriage through a dark glass at least as poorly. If they'd just admit the early leaders were wrong, and that Celestial Marriage isn't polygamous, I think this whole problem would go away.
This is pride, folks. Nothing but pride on the part of our leaders. They're too danged proud to admit they and our early leaders were wrong all these years. Were our leaders truly humble men, in tune with the spirit, we'd see a similiar revelation to the lifting of the priesthood ban presented to the members to be codified into our scriptures. But since this involves Joseph Smith and our leaders cannot admit Joseph ever made a mistake big enough to significantly impact the church today, they will never bend their knee and seek counsel from God on this one. They seem to be able to second-guess Brigham, but Joseph is untouchable.