There is a reason why such a serious sin as adultery ought to be avoided altogether, even if it is only as a foolish temptation contemplating the possibility of a plural wife. We all need greater light and knowledge. The only way it can be acquired is by heed and diligence to the commandments of God. Any other path is a diversion, intended to waylay you and prevent you from developing as God intends.
Peter urged in his second letter: “And besides this, giving all diligence, add to your faith virtue, and to virtue knowledge, and to knowledge, temperance, and to temperance, patience, and to patience, godliness, and to godliness, brotherly kindness, and to brotherly kindness, charity. For if these things be in you and abound, they make you neither barren nor unfruitful in the knowledge of our Lord Jesus Christ.” (NC 2 Peter 1:2) Peter explained the required steps for our progression. As soon as you acquire the faith to act, you next must add virtue. Virtue in turn leads to knowledge, because it is only through heed and diligence we gain knowledge.
As the people of King Benjamin demonstrated by their conversion to the truth, and their covenantal commitment to obey the truth, they gained the strength to do good. They no longer had any desire for evil: “Yea, we believe all the words which thou hast spoken unto us! And also, we know of their surety and truth because of the spirit of the Lord Omnipotent, which has wrought a mighty change in us, or in our hearts, that we have no more disposition to do evil, but to do good continually.” (NC Mosiah 3:1) A person who has the disposition to do evil and commit adultery is NOT yet converted. They are NOT yet redeemed. They still must repent and turn to God.
Joseph Smith explained that the gospel path requires us to increase in obedience to God. There is nothing static or stationary about the gospel. We must increase our obedience to participate in gospel conversion, “We consider that God has created man with a mind capable of instruction, and a faculty which may be enlarged in proportion to the heed and diligence given to the light communicated from heaven to the intellect: and that the nearer man approaches perfection, the clearer are his views, and the greater his enjoyments, till he has overcome the evils of his life and lost every desire for sin; and like the ancients, arrives at that point where he is wrapped in the power and glory of his Master and is caught up to dwell with Him.” (TJPS p. 51) If you remain attracted to adultery and fornication, you have not yet lost every desire for sin. Your views of right and wrong cannot be clear if you fail to see the evil in such disobedience.
There is a revelation for our day that says, “And that which does not edify is not of God, and is darkness. That which is of God is light, and he that receives light and continues in God, receives more light, and that light grows brighter and brighter until the perfect day.” (T&C 36:4) Light grows if you are in the gospel path. It grows brighter and brighter only when you forsake sin and give heed and diligence to the commandments. Adultery destroys that progress and robs you of light.
Alma explained, “[H]e that will harden his heart, the same receiveth the lesser portion of the word. And he that will not harden his heart, to him is given the greater portion of the word, until it is given unto him to know the mysteries of God, until they know them in full. And they that will harden their hearts, to them is given the lesser portion of the word until they know nothing concerning his mysteries; and then they are taken captive by the Devil and led by his will down to destruction. Now this is what is meant by the chains of hell.” (NC Alma 9:3)
Those who think they can follow God and yet commit adultery are deceived and giving heed to a false spirit. It is impossible to be both on the path to greater light and also engaged in such a serious sin.
Add to your faith virtue. It is perilous to do otherwise. You open yourself to deception and being led by false spirits and false prophets when you choose to ignore the commandment “Thou shalt not commit adultery.”