During sex, powerful bonding hormones are released such as oxytocin. Oxytocin is the same hormone that is responsible for forming the bond between mother and child. This powerful hormone also work to create bonds between individuals through sexual relations. Any sexual activity (including heavy petting) involving stimulation can assist in releasing this hormone. Because of its powerful bond forming capabilities, Oxytocin is sometimes referred to as a "pair bonding" hormone.
Once oxytocin is released into the bloodstream, it increases feelings of affection, trust, security, and contentment. This hormones calms the nerves and reduces fear and anxiety. It causes these two individuals to really feel like they are on one accord and enveloped in harmony. However, what happens when we are "pair bonding" with the wrong person and doing so before marriage?
Sex before marriage is very dangerous territory because now "oxytocin" is influencing our decisions. The hormone was created by God to form a bond of trust, tranquility, and peace between mates, mates selected by Him. However, we have abused and misused this hormone without realizing it and we are now forming "pair bonds" with "Mr. and Mrs. Wrong". So our feelings of affection, trust, security and contentment is false. When I say false, I am talking about the situation as a whole. Though the feelings may be very real,the relationship is built upon emotions and hormones instead of the Spirit of God. Emotions can only take a relationship so far. You may be "bonding" in the bedroom but hate each other in everyday life.
In conclusion, Oxytocin aids in forming soul ties by creating feelings of affection, trust, and contentment. When done outside of marriage it clouds one's judgement. This causes individuals to bond to individuals not suitable for them.