When Therapy Becomes a "Third": A PACT-Informed Caution

Stan Tatkin, founder of the Psychobiological Approach to Couples Therapy (PACT), defines thirds as “any people, activities, or things that draw attention away from the relationship at the cost of the couple’s connection.” In a healthy partnership, the couple itself is the primary unit of care; anything that consistently takes priority over that dyadic bond becomes a third, regardless of intentions or social acceptability (Tatkin, Wired for Love, 2017).

Most couples instantly recognize the usual suspects such as work, extended family, phones, vices, or affairs when boundaries collapse. But there is a quieter, socially sanctioned third that often goes unnoticed. Therapy itself, including therapists, therapeutic modalities, and psychological language, can function as a mismanaged third when it undermines rather than supports the couple’s safety, responsibility, and connection.

How Therapeutic Language and Therapy can Becomes a Third

We hear statements like:

• “My therapist said that…”

• “I read a relationship book and I think that...”

• “You are not regulated, therefore I shouldn’t…”

• “You’re just reacting from your trauma.”

• “That’s your attachment style talking.”
  

Any advice that shifts responsibility away from the couple’s collaborative process and into an external authority, without grounding in mutual regulation, consent, or attunement, risks becoming a third.

In PACT terms, this occurs when one partner uses expert language to control the narrative rather than co-regulate with their partner. Tatkin emphasizes that secure-functioning couples stay with the system of the relationship and not with third parties or external frameworks to resolve conflict and manage stress (Tatkin, 2017).

Why This Is Confusing and Harmful

Unlike affairs or substance use, therapy is socially reinforced as inherently good. This cultural valuation makes it harder to notice when something feels off, especially if the language being used is complex, authoritative, or psychologically framed.

Partners may begin to doubt their own instincts when they are labeled as reactive, defensive, or resistant to growth. Trauma researcher Judith Herman noted that in coercive environments, “the victim’s sense of reality becomes undermined” as they are taught to mistrust their perceptions (Herman, Trauma and Recovery, 1992).

Similarly, when therapeutic language is weaponized, even unintentionally, it can erode a partner’s reality-testing and emotional confidence, positioning one partner as the expert and the other as the problem.

Boundaries, Not Blame

To be clear, using therapy well is not the problem. What matters is how it is used.

Helpful approaches include:

• Couples integrate insights together

• Ideas are discussed in service of mutual safety

• Language supports connection and co-regulation

• Therapeutic language and approaches are built into shared principles

Mismanaged approaches include:

• One partner uses expert language to gain leverage

• Advice replaces collaborative sense-making

• Psychological concepts become weapons rather than tools

  
  

A Secure-Functioning Alternative

PACT teaches that secure couples:

• Co-regulate emotionally

• Stay with the couple system

• Use external frameworks only as supports, not substitutes for working together

  
  

Therapy can be an incredible tool for growth and healing, but like any powerful tool, it can be misused. When advice, psychological language, or therapeutic modalities start to pull attention away from the couple rather than strengthen the bond, they risk becoming a “third.”