A Mormon woman named "Brenda" (not her real name), wrote the following:

If Joseph Smith had sex with a woman who was married to another man that is adultery. God would have smote him. Much as many nonLDS want to show that Joseph was a sleaze, they cannot prove it. Their slander is recorded in heaven and their false accusation of the Lord's announced duly noted. Evil doing by the Lord's announced is not tolerated. Joseph could not remain a prophet as an adulterer. Polygamy is a sin when God has not commanded it. When commanded and not obeyed that is also a sin. Disobedience to Gods commands, especially by his anointed servants frustrates the work of God on the earth.

Below is Donna Morley's response:

Brenda, the purpose is not to show "Joseph was a sleaze," but to demonstrate that he had NO good reason for marrying the multitude of women and girls.

Consider---if Joseph Smith didn't have sexual relations with all the girls/women he married, then he disobeyed the revelation in Doctrine and Covenants 132:63, which states:

"But if one or either of the ten virgins, after she is espoused, shall be with another man, she has committed adultery, and shall be destroyed; for they are given unto him to multiply and replenish the earth, according to my commandment, and to fulfil the promise which was given by my Father before the foundation of the world, and for their exaltation in the eternal worlds, that they may bear the souls of men; for herein is the work of my Father continued, that he may be glorified." (D&C 132:63).

There's quite a bit in the above verse (as there is throughout D&C 132).

First, married women are not to marry any other man. If they do, they will be destroyed. Apparently, they don't get killed if they marry an LDS prophet. 

Second, Joseph was to "multiply and replenish the earth" with each woman he married. By NOT having sexual relations with his MANY wives, then Joseph was in clear disobedience. How else are you going to "multiply and replenish," if you don't have sexual relations? I don't see any other way around it. 

What then is the purpose of Joseph marrying the women, if he didn't have sexual relations? Can we rightly say that Joseph was in sin for marrying the women, without abiding by D&C 132?