When God made Adam he intended the first human to be God's companion. God wanted to be absolutely united with humans in a way that we have not known since the garden of Eden.
Later when He made Eve as a helper for Adam He still wanted to be united with humans similarly to how God is united as father son and spirit. Sin brought separation between God and humans and between humans.
Sex is representative of the coming together like it was in the garden of Eden and it is the only way we can get that close to another person.
When we have sex with a person, our body soul and spirit blend with that person's for a short time. Afterwards, there are connections and fragments that remain.
Humans have made sex cheap by doing it with so many people we became mixed up with so many unions that we no longer notice the bonds we are creating on ourselves.
This means God is no longer sharing you with just one other person as He created you but He has to share you with lots of other people and the spirits that may reside with them. How can God truly live through you if you fill your heart with the souls of other people?
By having sex with only one person is a way of showing God how much you love Him and give Him full ownership over your life.
Read this very good article:
"This is what happens when we have sexual experiences outside the confines of marriage. Actually, it’s what happens when we have sexual experiences regardless of our marital status. Every time we have a sexual experience, we are creating deep-rooted bonds with the other individual. There are a few different terms used to describe these bonds but the most popular, and the one I use in my book is “soul ties.”
4 Key steps to breaking soul ties:
Confess and Repent
Break and Remove
I DO NOT agree with the teachings in the following links but use it to point out how sexual bonding is known in multiple religious and naturalistic views: