If you believe with your whole heart and feel so utterly connected to someone that you feel you are married to them, would that be constituted as a marriage in the eyes of God? Adam and Eve did not have any ceremony. When did the first ceremony take place and what were the reasons such a ceremony was called for when none was used before? Must one be married by a “man of God” (i.e. a preacher)? Would a marriage by a justice of the peace (a man of law and not God) be a marriage in the eyes of God or just in the eyes of man?
The question you are referring to presented God’s view of marriage. Marriage is more than just a warm feeling or even a strong feeling towards another person. It is commitment. Malachi 2:14 says it well,
. . . the LORD has been a witness between you and the wife of your youth, against whom you have dealt treacherously, though she is your companion and your wife by covenant. (NASB) Malachi 2:14
In Malachi 2:14, God rebuked the men for divorcing their wives. He referred to the wives as companions or friends and then says they are “wives by covenant.” Notice that she is a wife by covenant and not because she feels like she is a companion or has feelings of friendship. She is not a wife because she feels married. She is a wife because she has made a formal covenant or commitment to remain with him.
Adam and Eve were unusual. God married them. There was no one else around “who could do the job.” Today most governments require a ceremony of some sort to legalize the marriage. God expects us to obey our government (Romans 13). So this requires some human to perform the marriage. A wedding ceremony alone does not make a marriage. It also involves a heart issue.
Sex does not make a marriage in God’s eyes. 1 Corinthians 6:16 helps us understand this.
Or do you not know that the one who joins himself to a harlot is one body with her? For He says, “THE TWO WILL BECOME ONE FLESH.” (NASB) 1 Corinthians 6:16
This wonderful passage tells us that when a man has sex with a harlot or prostitute, he becomes one body with her. Many people teach that when a man and a woman became one body, they are married. But this cannot be true since he calls the woman a harlot. In this passage the harlot is not the man’s wife. The harlot does not become a wife; she is still a harlot unless there is a commitment between them. Marriage is not just a commitment made before some individual. Marriage is also a commitment of the heart.
If your feelings for this man are strong and he is a Christian, having similar feelings for you, I would encourage the two of you to discuss marriage. If you a living with this man, God calls that sin. If he is not a Christian, you must stop seeing him. Such a marriage would not be blessed by God. Ask for the Holy Spirit to give you wisdom.