One of the tenatnt of the LDS church is that we believe in modern day revelation. That is, that God speaks to mankind in this day and age as well as he did anciently. Do you understand the premise here? It is, God can and does share counsel, concerns, inspritation, and direction pertient to the needs of the current times.
In other more clearer words....what may be necessary for one day and age may not be necessary for another. And, as new and current issues arrise, new and current revelation is need to deal with the changing times.
It happened before. In ancient times, animal sacrifice was a doctrine. In later times, it was done away. Revelation is precisely that. New doctrine, or changes to doctrine occur at the will and direction of the Lord.
Polygamy had a purpose at one time, More women were joining the LDS church than men, and therefore would not have the ability for an eternal marriage. Polygamy helped change that issue. Polygamy was not practiced generally, but by a selected few. As the issue no longer was an problem, the doctrine changed via revelation.
God is in control and God has the right to reveal as he seems fit. So the real issue for anyone is to gain a belief in modern day revealtion and a testimony of whether God does this or not.
Pray to God for such an answer. He has told us to do that in the Bible. See James 1:5 (and, getting an answer to your prayer, by the way, is a type of "revelation." Revelation does happen)