Sexual immorality in marriage may sound like a contradiction, but Scripture reveals that even within the sacred union of husband and wife, there are boundaries that must be honored. Adultery is the most obvious violation, but sexual immorality in marriage also includes selfishness, emotional manipulation, pornography, and abusive behaviors that defile the marriage bed (Hebrews 13:4).
The Biblical Call to Purity in Marriage
The Bible teaches that marriage is to be honored by all, and the marriage bed kept pure (Hebrews 13:4). This means that sexual intimacy is not only allowed but blessed within marriage—provided it reflects mutual love, respect, and fidelity. Immoral acts violate this sanctity, even if they occur between spouses.
Adultery: The Most Recognized Form of Sexual Immorality in Marriage
The clearest example of sexual immorality in marriage is adultery—when a spouse engages in sexual relations outside the covenant of marriage. Jesus emphasized that even lusting after someone else in the heart is equivalent to committing adultery (Matthew 5:28). This shows that God cares not just about our actions, but also our intentions and desires.
Selfishness and Abuse in the Marriage Bed
God designed sexual intimacy to be an act of selfless love and mutual giving. When one spouse uses the other for gratification, refuses intimacy out of manipulation, or engages in physically or emotionally abusive conduct, it dishonors the marriage covenant. 1 Corinthians 7:3-5 urges spouses to fulfill each other’s needs in love—not coercion or control.
Pornography and Mental Infidelity
Even if there is no physical cheating, viewing pornography or fantasizing about others corrupts the purity of marital intimacy. Jesus taught that lusting in the heart is sin. Pornography introduces comparison, dissatisfaction, and unfaithfulness into the marriage.
Emotional Affairs and Broken Trust
Affairs are not always physical. An emotional attachment that usurps the intimacy meant for one’s spouse can also be a form of immorality. Confiding in someone else with greater intimacy than with one’s spouse breaks trust and damages the spiritual oneness God desires in marriage (Genesis 2:24).
Can You Be Married to More Than One Person?
This is a challenging question because many Old Testament figures—like Abraham, Jacob, David, and Solomon—had multiple wives. However, the Bible does not present their polygamy as ideal. In fact, polygamy often brought strife and brokenness. For example, Abraham’s union with Hagar, though suggested by Sarah, led to division and distress (Genesis 16). God allowed certain things in the Old Testament due to the hardness of people’s hearts (Matthew 19:8), but Jesus clarified that God’s design from the beginning was one man and one woman joined as one flesh (Matthew 19:4-6).
Even when a spouse consents to another union—as Sarah did with Hagar or Abraham did when he claimed Sarah as his sister—those actions were born from fear or impatience, not faith. God never endorsed these moments as righteous. In the New Testament, church leaders are instructed to be “the husband of one wife” (1 Timothy 3:2), reinforcing God’s plan for monogamous, faithful marriages.
Sex During Menstrual Cycles: Moral or Not?
Leviticus 18:19 and Leviticus 20:18 both forbid sexual relations during a woman’s menstrual period. While this was part of the Old Testament ceremonial law, it carried with it the principle of respecting a woman’s body and honoring periods of impurity as designated by God. Some argue this command was tied to ritual cleanliness under the Old Covenant, and no longer binding under the New. However, others maintain that the principle of self-control, mutual respect, and honoring a spouse’s vulnerability still applies.
Romans 14 reminds believers to act according to conscience and not cause their brother or sister to stumble. So while the New Testament does not directly reaffirm the law about menstrual impurity to be sexual immorality in marriage, Christian couples should approach this issue with prayer, mutual agreement, and a desire to honor God and each other’s conscience.
Sex During Pregnancy: Is It Permissible?
The Bible does not explicitly forbid sexual intimacy during pregnancy. In fact, there are no scriptures that classify it as immoral. Instead, the focus in Scripture is on mutual love, consent, and care. 1 Corinthians 7:4-5 continues to apply: spouses belong to one another and are called to fulfill each other’s needs in love, not selfishness.
That said, pregnancy can bring physical and emotional changes. Couples should communicate openly, act with gentleness, and seek medical wisdom when needed. What may be physically comfortable or emotionally appropriate can vary by trimester or health status. But where there is love, respect, and mutual agreement, sexual relations during pregnancy are not biblically considered immoral.
As always, Christian couples should pray for wisdom and let the Spirit guide their intimacy in a way that honors the body, the marriage, and the Lord.
Honoring the Covenant With Heart and Mind
In the Sermon on the Mount, Jesus taught that sin is not limited to outward actions but includes the intentions of the heart (Matthew 5–7). This teaching is especially relevant in marriage, where love, faithfulness, and purity begin with our thoughts and motives. When Jesus said that looking at someone with lust is adultery in the heart (Matthew 5:28), He called all believers—including married couples—to a higher standard of internal holiness.
God designed marriage to reflect His covenant with us—a relationship of exclusive love and deep commitment. Anything that breaks that covenant emotionally, physically, or spiritually is immoral. That’s why guarding your thoughts, maintaining open communication, and fostering mutual respect is essential.
Repentance and Restoration
If a couple finds themselves entangled in immorality, the path forward is not condemnation, but repentance and grace. God offers forgiveness and healing. Through confession, counseling, and prayer, a broken marriage can be restored. God is faithful to redeem even what seems shattered.
Final Thoughts and Resources
Sexual immorality in marriage is not just about cheating—it’s about honoring the sacred trust, love, and unity that marriage represents. Fidelity is a matter of the heart, mind, and body.
Call to Repentance
If you have sinned in your marriage—whether in thought, word, or deed—Jesus invites you to repent and return to Him. His grace is sufficient. Confess your sin and ask Him to heal your heart and your home.
Prayer:
Lord Jesus, thank You for Your mercy and grace. I confess the ways I’ve dishonored my marriage, whether in action or in thought. Please forgive me, cleanse me, and restore the covenant You’ve blessed me with. Help me to love selflessly and honor my spouse as You have commanded. Amen.