People Today think they are not married if they don't have a commitment on paper. This is quite the convenient excuse for adultery, promiscuity and fornication.
If anyone has every lay with another person, they know full well the emotions, thoughts and concerns of the heart that arise. This is because something deeper is stirring. Something more than simply lust of the flesh. The Word speaks to this truth and spiritual reality, warning people not be deceived or corrupted by the empty logic and excuses of men.
That is why a man leaves his father and mother and is united to his wife, and they become one flesh.
- Genesis 2: 24
The act of consummation is the act of two becoming one; marriage. The uniting of two people is a vow before God. How Isaac came to 'marry' Rebecca is quite insightful.
I think every person who has ever had sex with another person has became one in spirit and in flesh with them. There is evidence of this reality when looking at the outcome of broken people, broken homes and broken lives produced from infidelity, divorce, adultery, etc.
The opposite evidence is also clear when looking at the outcome of homes with couples who are faithful, loving, respecting and honoring of one another. The outcome of both paradigms can usually be perpetually seen in subsequent generations. However, cycles can be broken and lost.
I share this in light of God's mercy, patience, forgiveness and abundance of grace upon grace already poured out. Yet, once the individual understands their sin, they are now held accountable; those whom the Holy Spirit convicts and compels to turn and are called to repent. Those who scoff either do not yet see or are not called.
God bless and have mercy on all, clarifying your certain calling.