Why with her he watches funny series and with me he insists on watching only art-house cinema? PHOTO: Mart Production/Pexels.
Insecurities That Sting
Sometimes jealousy has nothing to do with your partner’s infidelity, but with the feeling of being excluded from plans. But it still annoys you just the same.
By Paka Díaz
May 8, 2026 / 07:30
Let’s set the scene: a grown man who is fully established regularly meets with his sister. They still share confidences as if they were 13, go out to eat on their own, exercise together, and when they joke, it seems as if only the two of them exist… Everything feels very natural until the spouse who cannot stand that proximity between her husband and his sister-in-law collides with this dynamic. She may be a gorgeous person, but she cannot help feeling excluded. Even though she is clear that this is not about infidelity, she experiences some odd jealousies that are hard to control. And that makes her feel guilty for not being able to overcome that insecurity. It’s not that she can’t stand her sister-in-law; she can’t stand her husband’s relationship with his sister-in-law.
According to psychologist Emma Trilles, author of Antídoto contra la infidelidad (Plataforma Editorial), these feelings are more common than they seem. “Family relationships can awaken unexpected insecurities within the couple,” she explains. And the relationship between siblings occupies a very special place.
The Feeling of Being Left Out
Siblings are often the first emotional companions in life. They have shared childhoods, secrets, conflicts, and alliances for years. That bond can remain very strong even in adulthood. “For many people, the brother or sister continues to be an important emotional reference,” notes Trilles. When a partner enters the scene, those bonds must be reorganized. But this does not always happen automatically.
One of the most frequent sources of discomfort is the sensation of exclusion. After all, there are two people who share very old codes: childhood memories, private jokes, family stories… In those cases, the third person may feel outside of that world. “It’s not so much romantic jealousy as jealousy of belonging,” explains Trilles.
She emphasizes that we are not dealing with a case of a toxic sister-in-law. Simply, it is someone with whom your partner gets along well, and that triggers the sense of abandonment, insecurity, or being snubbed.
The Emotional Hierarchy
The wife or husband expects boundless love from their spouse and to be the first option in everything. That works in romantic movies, not in real life. In the real world, the person you train with isn’t always your partner because he doesn’t like running and you do. And you might not even share the same sense of humor, because what amuses you is Chiquito and he prefers Faemino y Cansado. These are small details that would not matter much until the sister-in-law fills that emotional space.
It is easy to fall into the trap of thinking that he should have his priorities clear, as if laughing with his sister were almost an infidelity. Doubts, insecurities, and, finally, resentment arise. Wondering why he doesn’t do that with me and with my sister-in-law, yes. Sometimes fear isn’t rational. But it is emotional,”
the person may wonder whether their partner shares with their sister an intimacy that they do not share with her.
How Should the Relationship Between Siblings Be?
The psychologist acknowledges that these insecurities arise, in many cases, from a complex relationship within the family itself. Those who have had distant or conflictive ties with their siblings may perceive the level of closeness of other families as strange. They may even interpret it as a threat. “Personal experience heavily conditions perception,” notes Trilles.
What is normal for one person, such as talking to a brother every day, can be excessive or even intolerable for another. It is then when the mind lets loose imaginations that hurt, imagining that her husband prioritizes the sister-in-law, and that circumstance worsens the anxiety even more.
Afrontar los celos fraternales
The first step is to recognize the feeling without judging it or pathologizing it. “Jealousy doesn’t always indicate a real problem,” explains the psychologist. Sometimes it only points to an insecurity that needs to be heard.
Talking about it with the partner is usually more useful than keeping it silent. But the conversation should focus on the emotion itself, not on accusations. For example, explain that sometimes there is a feeling of being left out, rather than reproaching the relationship with the sister.
Integrate Rather Than Compete
In many cases, the solution isn’t about reducing the bond between siblings, but about including the spouse. Inviting the partner to their gatherings with the sister-in-law is a good start. Going along without viewing the sister-in-law as the lover and the feeling of being ‘the other’ also helps. In other words: normalize and de-dramatize something that is nothing more than a familial bond. “When the partner feels integrated into that family bond, the sense of threat tends to disappear,” explains Trilles.
Sharing some plans or creating common spaces can help build that integration. Because in the end, family relationships do not have to compete with each other. “Love doesn’t work like a zero-sum game,” the psychologist concludes. Because, as she stresses, “the couple bond can coexist perfectly with family ties, as long as everyone finds their place.”
