An open relationship is commonly characterized as a partnership in which one partner permits the other partner to have sex with other people. The two main forms of open relationships are polyamory and swinging. Polyamory is when emotional love supposedly includes extramarital affairs. Swinging is when there is only recreational/casual sex involved in extramarital affairs
The Bible does not mention polyamory, swinging, or the concept of an open marriage directly anywhere. The definition of one partner consenting to the other spouse having sex with other individuals is utterly alien to the Bible. The Bible defines sex within marriage as sacred (Hebrews 13:4).
The Bible describes sex outside marriage as immoral and adulterous (1 Corinthians 6:13, 18; 10:8; Galatians 5:19; Ephesians 5:3; Colossians 3:5; 1 Thessalonians 4:3).
The question is usually posed as to whether a polyamorous arrangement should be labeled adultery if the other partner accepts, supports, or even participates in it. An unambiguous answer is yes, it’s adultery! God is the one who determines what adultery is and what marriage is. God deemed sex outside of marriage to be adultery in His Term (Exodus 20:14). Giving permission to sin to a partner does not overrule the law of God. We don’t have the power to make exceptions to what was considered immoral by God.

Aside from the divine declarations that open relationships are sinful, they also do not satisfy what the Bible says about marriage. If several ‘flesh’ is involved, a married couple will not be’ one flesh’ (Genesis 2:24). If the love is split between other persons, a married couple can not truly love one another. True intimacy does not exist if what is meant to be private is shared with others. Polyamory doesn’t mean marriage. A marriage is in no way intended to be open to sexual relations outside the marriage.
Polyamory is “poly-lust-ory,” in truth. And there is nothing beautiful about it. “This marriage perversion confirms that “the intention of our hearts’ thoughts is constantly only bad,” and that, without God, “man does what is right in his eyes (see Genesis 6:5 and Judges 21:25)
Below are a few biblical reasons open relationship is not right:
We bend the scriptures to suit our needs
People misrepresent and bend Scripture to satisfy their needs. As per the Bible, adultery defiles marriage. You shall not commit adultery! This is not restricted to out-of-marriage sex. God commands us to desist from all sexual immorality, including premarital sex, masturbation, incest, voyeurism, bestiality, and public nudity. But we want to justify our behaviour, like everything else, to ease our minds and maybe even deceive our souls. We can’t be the proverbial ostriches who hide our heads in the sand as Christians and justify this as a norm.
It isn’t part of the plan of God
Do you perceive sexual acts as part of being one flesh? If you don’t, this may be the reason you believe it’s perfect to have an open relationship. God created the One Flesh relationship. Marriage and sex are meant to be part of the perfect design of God. Genesis 2:24 says that “Man will leave his family, join to his wife, thus becoming one flesh with her.”
We harm our spirit and maybe our wellbeing when we step outside to have multiple sex partners. Sex brings people together physically, mentally, and spiritually. Mark 10:9 has also stated that it is a strong force when people are together. Hence, they are no longer two but a single flesh. Consequently, what God has joined together, let no man divide.
It’s a sin
Ephesians 5:3 is fairly straightforward on sexual immorality. “But there must not be even a sign of sexual immorality, impurity, or covetousness amongst you, for these are unacceptable for the children of God.” Sex with anyone who isn’t your partner is one idea of sexual immorality.
Adultery is another name for this act. You can label it as “swinging” or having an “open relationship,” but it is a sin according to the Bible. When individuals excuse this behaviour, it may allow them to feel better for some time. Nonetheless, they are aware deep within that sex outside marriage is wrong.
People are manipulated
TV shows and blogs love to glamorize sex outside of marriage. Many individuals believe that they are not unfaithful until they physically contact somebody other than their partner. But the more visual adultery you commit, the more likely you will end up participating in an open relationship.
Jesus said, “But I say to you, whoever looks at a woman to lust for her has already committed adultery with her in his heart.” Not many speak today about sin and the implications of our acts because this will decrease the church’s income streams. We are being misled because we are not interested in hearing our faults and sins.
See also – Loving Others Like Christ Loves the Church
People don’t protect their hearts
Webster’s Dictionary defines adultery as “consensual sexual intercourse between a married man and somebody other than his wife or between a married woman and someone else besides her husband.” Satan wishes us to be out of control so that we drift farther away from God and His mission.
As recorded in Romans 10:17, “Satan comes immediately and takes away the word that has been sown in them.” We also need to pay close attention to how the devil uses situations to manipulate us, even though it seems to be harmless.

It’s selfish
Let’s be honest and admit it’s self-centered and parsimonious to agree to adultery and call it “an open relationship” You don’t need to be a believer to find out this. But great sex doesn’t quite make a good marriage. Good sex is the product of a good marriage. Sex is special because of the way it physically ties two people together sensitively and intimately.” What about faithfulness? Isn’t it important?
It’s not enough that we can mould marriage into what we want it to be. If we change the meaning of marriage, we reshape family. And everything that broadens the importance of marriage and family into nothingness takes us a little closer to removing the foundation so essential to our existence.
Put whatever tag you want on it, but an open relationship is a sin, and it doesn’t matter how many religious texts you try to back it up with erroneously. Pray and encourage the Lord to be your heart’s minister.
You should read this and learn – Choosing the Right Internet Content for your Spiritual Life
Reference
Can Christians Have an Open Marriage? – Beliefnet