Two people share a bed, bills, children, and a routine. But they no longer share desire.
Sometimes, one of them—or both—finds outside the home what has stopped happening within it. For those experiencing this, the question is often painful: if affection still exists, why does sex vanish from the couple only to reappear somewhere else?
Short answer: there is no single cause. Sexuality research and clinical listening point to a combination of factors: routine that extinguishes novelty, unspoken resentments, exhaustion, difficulty communicating fantasies, and the confusion between intimacy and eroticism. Seeking sex elsewhere can be an attempt to reclaim a part of oneself—but this explains, not justifies, and has real consequences for trust. This text is for educational purposes and does not replace professional evaluation.
Desire Is Not a Stockpile That Runs Out
It's common to think of desire as something that either exists or doesn't. Research in the field shows something different. Researcher Rosemary Basson described responsive desire: in many people, especially in long-term relationships, desire doesn't arise spontaneously but appears after a favorable context—time, touch, connection, absence of pressure. When a couple expects desire to appear "out of nowhere," they conclude it has died. Often, it simply hasn't found the right conditions to emerge.
Intimacy and Eroticism Don't Always Go Hand in Hand
The psychotherapist Esther Perel popularized an idea that many couples recognize: the security of life as a couple nurtures intimacy, but eroticism often needs some distance, mystery, and novelty. When a partner becomes just "the father of my children," "my partner in bills," or "my logistics colleague," the role of an object of desire can become vacant.
Outside the home, a person finds someone who doesn't know their flaws, their exhaustion, or their fights. This other person is, in large part, a screen for fantasy.
What's Usually Behind It
- Accumulated resentment. Unresolved hurts rarely manifest as arguments; they manifest as a refusal of the body. It's hard to desire someone you feel owes you something. See resentment in relationships.
- Exhaustion. Work, children, and the mental load reduce the energy available for pleasure. Often, desire doesn't die: it's the first item cut from an impossible schedule.
- Unspoken fantasies. Out of shame or fear of judgment, many people don't talk about what they desire with their partner and start to imagine that they could only experience it with someone else.
- A search for oneself. For some, the external encounter has less to do with the other person and more with feeling desirable, alive, or free again.
- Mismatched rhythms. When one person repeatedly initiates and the other refuses, both get hurt: one feels rejection, the other feels pressure.
What Psychoanalysis Helps Us Think About
Freud observed in 1912 that for many men of his time, tenderness and sensuality seemed to be separate: one desired where one did not love, and did not desire where one loved. This observation was born in a specific historical context and should not be applied to everyone, but it touches on something still seen in clinical practice: sometimes the loved one becomes associated with family, duty, and protection, and desire seeks a place "outside the law," where there is no history or expectation.
This is an interpretive reading, useful for reflection, not a proven law. Empirical evidence shows that long-term sexual satisfaction depends heavily on communication, a willingness for novelty, and how the couple handles conflict.
Explaining Is Not Justifying
Understanding why someone seeks sex elsewhere does not make breaking an agreement acceptable. Infidelity usually causes intense pain, loss of trust, and often, symptoms of significant distress in the person who was betrayed. There are also couples with consensual non-monogamy agreements, and that is a different situation. The point here is the secret pursuit that breaks what was agreed upon.
Everyday Examples
Marina and Paulo haven't had sex in months. He works late; she feels she carries the household burden alone. When he approaches her, she feels anger, not desire. The problem that appears in bed was born from the division of their life.
Rafael started exchanging messages with a colleague. He says he doesn't know why. In conversation, he realizes it's the only relationship where he feels admired, not criticized.
Questions for Reflection
- When was the last time you felt desired—and when did you desire someone?
- Is there a hurt you've never said out loud?
- What are you seeking outside the relationship: another person or another version of yourself?
- Can you and your partner talk about sex without accusation?
What Can Help
- Name what is happening without turning the conversation into a judgment.
- Separate desire from fights: resolve conflicts outside the bedroom.
- Create context for responsive desire: time, touch without obligation, novelty.
- Talk about fantasies carefully, without making demands.
- Seek couples therapy or individual counseling when the pattern repeats.
If this topic has stirred up guilt or rumination, it might help to read why I can't stop thinking, self-esteem, guilt, and boundaries, and low sexual desire: what to do. To understand the dynamic between impulse and rule, see id, ego, and superego.
Frequently Asked Questions
Does a lack of sex in a marriage mean the love is gone? Not necessarily. Love, intimacy, and sexual desire can vary independently.
Do people who are unfaithful not love their partner? There's no rule. People are unfaithful for various reasons, including while still loving their partner. That doesn't lessen the damage.
Can desire return? In many couples, yes, especially when conflicts and exhaustion are addressed and there is room for novelty.
References
- BASSON, R. The female sexual response: a different model. Journal of Sex & Marital Therapy, 26(1), 2000.
- PEREL, E. Sexo no cativeiro. Rio de Janeiro: Objetiva, 2007.
- FREUD, S. Sobre a mais comum depreciação na vida amorosa (1912). In: Obras completas.
- MARK, K. P.; LASSLO, J. A. Maintaining sexual desire in long-term relationships. Journal of Sex Research, 55(4-5), 2018.