Praying for forgiveness of sin
Sin is doing your own will and in that way conflicting with God's Love, with God's Righteousness, with God's 10 Commandments and with your body.
God's 10 Commandments are about loving God, your neighbour and yourself. But at the same time about righteousness towards God, your neighbours and yourself. So acting against God's 10 Commandments actually means going against God, Love and Righteousness, against your neighbours the same way and also against yourself. That is sinning/sin.
The same is applicable with sinning against your body by sexual acts. The Bible mentions adultery, fornication, prostitution/having paid sex, homosexuality, sex with family, sex with children, sex with animals, sex with corpses and rape. That is also sinning/sin.
"Flee fornication. Every sin that a man doeth is without the body; but he that committeth fornication sinneth against his own body".
Adultery and fornication also binds people and their sins together spiritually. So you can say each person that does so is wearing chains of sin.
In the current world free sex is taught and practiced and as people living on this world we follow it's teachings and laws. Possibly not being aware about how God sees this and not knowing about the spiritual and bodily consequences. Thus laying many chains of sins...
And even Christians do such things as we can read in 2Corinthians12:21 in which Paul tells us that. And he also tells that you should stop sexual immorality in your doings and ask God for forgiveness:
"lest again when I come my God should humble me before you, and I should mourn for many of them that have sinned heretofore, and repented not of the uncleanness and fornication and lasciviousness which they committed".
"You shall not commit adultery", Exodus20:14.
I thought getting married was not a synonym for having sex; and not the other way around. And I didn't know God's ways/rules, neither the consequences of my behaviour...
Ephesians 5:31 "For this reason a man will leave his father and mother and will be joined to his wife, and the two will become one flesh".
1Corinthians6:16 "do you not know that anyone who is united with a prostitute is one body with her? For it is said, “The two will become one flesh".
Having free (or paid) sex with multiple persons even will bind you with many people and accordingly also their sins, ways and possible diseases also and thus you take all of it on your way.
It starts with being aware of this, that it is sin, that it makes you a prisoner and that it damages you spiritually and bodily. Then you should stop sinning that way and ask God for forgiveness in the name of Christ Yeshua. And maybe also a bodily check-up is wise so when you eventually meet a suitable partner you marry will not get a veneral disease because of you and your sexual history.
"Sober up as you should, and stop sinning! For some have no knowledge of God", 1 Corinthians 15:34
Check if you are still living an old life: Check your old & current life
Read more about God's Commandments here: Living according to God's Will & Commandments