A commenter stated well (Kathryn): "I'll have to wait for this to be taught as 'official' doctrine in some future General Conference. Maybe it will be shouted from the roof tops in great rejoicing and relief by those who think it makes more sense and clarifies the apparent conflicts between various scriptures in which the Lord either condemns or commands multiplicity of wives. It has always seemed inconsistant [sic] and difficult to understand or explain. . . ."
The premise is that the basic marriage law is monogamy, but under certain circumstances, some people may be asked by God to have plural wives. She compares this diversion from monogamy to the great sacrifices of Abraham with Issac as well as Christ with his death. She points out that in the end, there was always a "ram in the thicket," or rather, an escape, a way out. She suggests that just as there was an end to Christ's suffering as well as an end to Abraham's fear in sacrificing his son, there will also be an end/way out of polygamy (if one desires it).
I'll share a couple of my most favorite parts -- Cassler brings up a few points, perhaps rumors/traditions, that have been floating around in LDS culture regarding polygamy and suggests that they very well may just wrong -- we really can't prove them (so we should stop perpetuating them!)
Some in LDS culture assume that polygamy is not merely a doctrinal necessity but a circumstantial necessity in the hereafter. Generally this assumption takes one of two forms. In the first form of the assumption, some assert that there will be more women who inherit the celestial fullness than men, and since everyone in the highest level of the celestial kingdom is married, polygamy then must follow as a natural consequence of the sex ratio there. This “folkways” is unsound both doctrinally and demographically. There is simply no basis for assuming a celestial sex ratio highly skewed in favor of women.
First, how could God be no respecter of persons and create a system where one spirit, because of gender, has a much better chance of reaching the celestial kingdom than the other gender? If God is the author of all fairness and if gender equality is a foundational principle of the gospel, he could not have authored such a system. Even if this system were somehow fair, for such an outcome to ensue would mean that the male gender was disproportionately assigned to or an attribute of weaker spirits. There is no doctrinal or scriptural basis for such a belief.
For those who feel polygamy is ubiquitous in the celestial kingdom, this belief demands that, at a minimum, twice as many women make it to the celestial kingdom as men. But human demographics argues against such a conclusion. Approximately 106 male babies are born on earth for every 100 female babies born.  More males have existed on earth than females. Yet by age five, the sex ratio is about 1:1, for male babies are more susceptible to genetic disorders. Therefore, a large number of males die before the age of accountability and are automatically saved in the celestial kingdom. Also, male deaths through such mechanisms as the wholesale killing of male children by an enemy power (e.g., in Moses’ time and in Jesus’ time), or males laying down their lives in righteous defense of family and homeland also increases the pool of males eligible for the celestial kingdom. Using established demographic procedures, several BYU sociologists declare in perhaps only a partially tongue-in-cheek essay that they can demonstrate there will be more males in the celestial kingdom than females! 
All the foregoing serves to make the point that it is by no means clear that females will outnumber males in the celestial kingdom. There is absolutely no scriptural or empirical basis upon which to assert the sex ratio of the celestial kingdom. If we cannot confidently assume that there will be more exalted women than exalted men, then one cannot conclude that polygamy must then follow.
The second form of the assumption that polygamy is a circumstantial necessity in the celestial kingdom is the notion that one Heavenly Mother is incapable of producing and nurturing the vast numbers of spirit children that Heavenly Father appears to have fathered. After Christ comes, “time is no longer” (D&C 84:100; D&C 88:110). With God, past, present, and future are continually before his eyes (D&C 130:7). What this means, no one knows in this life. But clearly it means that the same temporal constraints do not exist for Gods. What, then, does it mean to say that something “would take too long” for a God? Additionally, it does not appear that God is in some great hurry to do his work. It may have taken billions of years to produce the universe and, eventually, our solar system. Why does he need to rush the production of spirit children? Furthermore, we do not know anything about how spirit children are organized or how long it takes to organize them.
But how could one Heavenly Mother take care of so many children? This question takes on its true character if we change it to ask: How could one Heavenly Father take care of so many children? We believe Heavenly Father is capable of loving each one of us completely. If a single he has such abilities, why do we doubt that a single She has the same?  In addition, Heavenly Father and Heavenly Mother do not exist as a typically modern nuclear family unit--they have an entire and very large eternal family organization to help them. Think of all that Christ, Their Son, accomplished in creating numberless worlds at a time when he did not yet possess a body and had not yet entered into the new and everlasting covenant of marriage. We must suppose that our divine parents have plenty of help in bringing to pass the immortality and eternal life of man.
Additionally, I really enjoyed learning about who was sealed to whom in the early days of the early LDS Church and how confusing it all got. It seemed most important then just to be sealed, but it didn't quite matter to whom.
Thus it appears that choosing to enter sacred covenants of sealing and remaining worthy of those covenants is all that matters from the standpoint of the individual’s exaltation as a member of God’s eternal family--the actual people to whom one is sealed might or might not change in the re-forging of the great family link of all God’s exalted children. Even if you are sealed to an unworthy person, it is as if that person is a stand-in for one who is worthy--whom you may not even meet in this life. This explains why the Church does not cancel the sealing of a wife in a divorce situation unless another marriage sealing is to take place; because what matters is that the wife chose and presumably remains worthy to be sealed to a worthy Melchizedek Priesthood holder--even though she will most likely end up having that sealing transferred to someone else. Her first husband remains, as it were, a “stand-in” until a transfer can take place. 
Such stand-in, or “proxy,” marriages were common in the early Church, because in the first several decades of the restored Church, one could not be sealed to loved ones who had not been baptized into the Church before they died. Surviving family members were sealed to General Authorities to assure their exaltation. Widows whose husbands had died before hearing the Gospel were sealed to a general authority as the authority’s wife in order to assure their exaltation, and then typically had their husbands sealed to the same General Authority as a child so as “to keep him in the family”!  This resulted in many women becoming plural wives because of the mistaken understanding that they could not be sealed to their dead husbands and could not gain their exaltation unless sealed to someone as a wife. For example, women who had never even met Joseph Smith while he was alive were sealed to him after his death; also, one woman had her aged mother sealed to her (the daughter’s) husband shortly before the mother died so that the mother could receive her exaltation. Wilford Woodruff had over 400 of his dead female ancestors sealed to him as wives. These practices seem to indicate that the parties involved understood that the man in question was more of a stand-in or proxy so that the woman could receive the marriage ordinance and thus her exaltation, than an understanding that these women were married in some meaningful sense to these particular men for all eternity. For example, what can it mean to have a dead woman sealed to you, whom you have never met in this life, whose will on the matter you cannot possibly know, and who is in fact one of your great-great grandmothers? Or to have your own mother-in-law sealed to you as a wife? Or, in the case of a woman, to be sealed to a dead man whom you have never met, and whose will on the matter you cannot possibly know? These marriages make sense best as proxy marriages. Indeed, when President Wilford Woodruff announced in 1894 that women could be sealed to their dead husbands (and children to their dead parents) even if the deceased had not been baptized before their deaths, many thousands of sealing transfers took place to rightfully reorganize family lines. 
I wonder if there was a differentiation between the word "sealing" and the word "marriage" in the past. Today, we tend to group them together as though they are one, but if you separate the two, it sure would explain a lot of things. Women could be sealed to a man, yet not really be "married" to him in the full sense of the word.
One question I had was regarding the very strong statements by people in Church history regarding the practice of polygamy, such as (taken from The Juvenile Instructor blog):
[Polygamy] was at the center of LDS theology, it was emphasized within Mormon practice, and it was exemplified by all ecclesiastical leaders. The fact that it was at the center of the Mormon ideal image transcends demographics. A few examples help provide a glimpse:
- Plural wife Esther Romania Bunnell Penrose proclaimed polygamy as “the platform on which is built Endless Kingdoms and lives and no other or all combined principles revealed can be substituted as a compensation.”
- Brigham Young’s counselor Daniel W. Wells, when under oath in the Reynolds Trial, explained that if Mormons “failed to obey it [polygamy] they would be under condemnation, and would be clipped in their glory in the world to come.”
- Joseph F. Smith in 1878 protested against the “false idea” that monogomy was enough for the highest glory, and that “whoever has imagined that he could obtain the fullness of the blessings pertaining to this celestial law, by complying with only a portion of its conditions, has deceived himself. He cannot do it.”
- As late as 1884, Apostle Moses Thatcher declared polygamy was “the chief corner stone in the hands of [God].”
- That same year, George Q. Cannon emphasized that he “did not feel like holding up his hand to sustain anyone as a presiding officer over any portion of the people who had not entered into the Patriarchal order of Marriage,” and that everyone who is capable “must have more than one wife at a time in order to obey that Law.”
Regarding statements like these, Cassler states:
Last, nonscriptural statements by early Saints indicate that they believed polygamy to be the mode of married life in the celestial kingdom and that quantity of wives in the hereafter is a sign of a man’s degree of righteousness, which statements seem to support the “reward” interpretation.  However, we must remember that these statements were made in that period of time where some confusion existed about the sealing order of heaven. It was thought that one could not be sealed to dead relatives who had passed away without being baptized. Widows felt they had to be sealed to a general authority to assure their exaltation; remember that men thought they had to be sealed to General Authorities as their children, and that all must eventually be sealed directly or indirectly to the head of the dispensation (Joseph Smith) and that is where their sealing duties ended. Thus, many early General Authorities had many wives and many children because of the confluence of these ideas about sealing and the God-given commandment to practice polygamy. In a sense, then, the actual practice of polygamy in the early Church was profoundly affected by some confusion over the sealing order. It is conceivable that this situation affected the understandings of these early Saints on the topic of husband-wife sealing in marriage, as well.  We note that this confusion was cleared up by the same prophet in whose tenure God rescinded the exceptional commandment to practice polygamy: Wilford Woodruff. Indeed, we believe it is no coincidence that this was the case. In rescinding polygamy in 1890 in the context of the constrained views of the time about sealing, Wilford Woodruff, acting as the Lord’s mouthpiece, was seemingly placing exaltation out of the reach of many persons whose immediate family had not received the Gospel before death. The sorrow of this situation could only have been rectified by removing the confusion over sealing. Thus, resolving the confusion over sealing in 1894 was a necessary appendage to the rescindment of the commandment to practice polygamy in 1890.I also always consider that those people were commanded to live polygamy, so if they were going against a commandment, wouldn't they be condemned? Wouldn't you think they'd try and support it the best they could?
So, again, this isn't Church doctrine, but it gives me some good pondering.
(bold emphasis added)