You sound very sincere and I commend you for that. Guidance is a very difficult thing and I doubt if there is a man of God who has achieved anything significant who hasnt at some time slipped up in this area. This has often been very devastating for the person because they had felt so sure. Often they even felt God had let them down until eventually they discover they had been too hasty and hadnt sought sufficient confirmation. But God readily picks up anyone who is willing to admit he was wrong.
Scripture says we must not allow our liberty to be the cause of someone elses fall (Romans 14:20-21; 1 Corinthians 1-2, 7-13). The fact is that all men are at some time tempted to think of adultery and the thought of polygamy can be very appealing and if there is a difference between polygamy and adultery, few men, especially in our society would be able to differentiate. Men hear of polygamists in other cultures and of non-Christians doing things, but to hear of a Christian polygamist presents a whole new range of possibilities for Satan to play havoc in a mans imagination and lead him to at least sin in his heart. Temptation must come, said Jesus, but woe to him who causes it, it would be better for him to have a millstone put around his neck and he be thrown into the sea.
We are told over and over in Scripture to uphold the law in ones country, unless that the law forbids us to act righteously or evangelize (Romans 13:1-7; Titus 3:1; 1 Peter 2:13). Everyone knows polygamy is illegal in the US and many other countries. Any attempt to get around the legal problem is against the spirit of the law and Scripture tells us to do that which is right not just in the eyes of God but in the eyes of man (Romans 12:17: 2 Corinthians 8:21). Even non-Christians tend to see polygamy as immoral. I am reminded of 1 Corinthians 5:1-2, "It is actually reported that there is sexual immorality among you, impurity of a sort that does not even occur among the heathen . . . you ought to mourn until the person who has done this is removed from your fellowship." Moreover Scripture commands us to obey our spiritual leaders (Hebrews 13:17). I doubt that you did this. You might even have rebelled against having anyone over you.
Finally, every instance of polygamy recorded in Scripture that I can think of, details family disruption and disharmony. For instance, the intense feud leading to rape and murder in King Davids family all centered around a sons lust for his half-sister. Had she been his full sister, such a thing would be most unlikely. We find Hannah being severely provoked by her rival, her husbands second wife (1 Sam 1:6-7), we find bitterness between Sarah and Hagar, and between Jacobs wives and concubines. Scripture seems to go out of its way to paint polygamy as most unwise. Why, then, would the God of the Bible lead someone to do something that he himself has painted as unwise?
It has been suggested that polygamy is acceptable because the New Testament does not specifically repeal the Old Testament tolerance of polygamy and because Martin Luther, when forced into a tricky political corner, drew attention to this fact. To use this logic one would have to conclude that we should execute heretics because this was not only allowed but commanded in the Old Testament, was not specifically repealed in the New Testament, was advocated by the reformers, and too bad if its illegal.
Pharisees challenged Jesus:
Skyrocketing divorce rates over recent years is a sad commentary on the worldliness of modern Western Christians. Don't let this harden you, however, to Jesus' response, which I believe is as relevant to polygamy as it is to divorce.
Christ emphasized that there is a significant difference between what God permitted under the Old Covenant, due to peoples hardness, and the way that people should act. Jesus had just explained the way it was from the beginning. He quoted Genesis saying that two (not three or more) shall become one flesh (Matthew 19:5,6).
Sadly, in the light of all of the above, I am forced to conclude that the chance that your being led to take a second wife was a product of the lust of the flesh or the wiles of Satan, is enormous. I recognize that facing such a possibility would be extremely painful for you. Everything within you will want to rebel against this. It would take a very brave and strong man to face up to it. If you are willing to do so, I shall do my utmost to try to support you.
In most cases, marriage vows included something along the lines of forsaking all others, and even if not expressly stated, it was no doubt in the husbands heart when he made those vows before God. Polygamy would therefore be a breaking of those vows.
Despite Solomons behavior, and its tragic results Deuteronomy 17:17 gives this command to every kings, He must not take many wives. And we all know the New Testaments instructions to leaders, be they overseers, deacons or elders:
1 Timothy 3:2 Now the overseer must be above reproach, the husband of but one wife, temperate, self-controlled, respectable, hospitable, able to teach
1 Timothy 3:12 A deacon must be the husband of but one wife and must manage his children and his household well.
Titus 1:6 An elder must be blameless, the husband of but one wife, a man whose children believe and are not open to the charge of being wild and disobedient.
(Emphasis mine)
Leaders must set an example to the congregation. And what example should the congregation be following? Monogamy.