What makes two people compatible? While chemistry and attraction spark relationships, long-term compatibility depends on deeper psychological factors. Research reveals what actually predicts relationship success.
Similarity vs. Complementarity
The debate between "opposites attract" and "birds of a feather" has a clear winner in psychological research: similarity wins.
The Similarity Advantage
Studies consistently show that couples who are more similar in personality, values, and attitudes report higher relationship satisfaction. This similarity operates on several levels:
- Values similarity: Shared core values about family, money, religion, and lifestyle predict long-term success
- Personality similarity: Similar Big Five profiles correlate with relationship satisfaction
- Attachment similarity: Two secure partners fare best; similar insecure styles may understand each other
- Intelligence similarity: Similar cognitive ability predicts satisfaction, though direction doesn't matter
When Complementarity Works
Complementarity (differences that balance each other) can work in specific domains:
- Dominance-submission: One partner being more dominant can reduce conflict over decisions
- Practical skills: Different strengths can make partnerships more functional
- Emotional expression: An expressive partner may help a reserved one access feelings
However, complementarity in core values rarely works. Hoping someone will change or balance you fundamentally usually leads to disappointment.
The Role of Attachment Styles
Attachment style significantly predicts relationship compatibility:
Secure + Secure
The gold standard. Both partners can navigate conflict, communicate needs, and maintain connection through challenges.
Secure + Insecure
A secure partner can help an insecure partner develop earned security over time. The secure partner must be patient and not take insecure behaviors personally.
Anxious + Avoidant
The most common dysfunctional pairing. Creates an addictive push-pull dynamic that feels like passion but causes pain. Can work only with significant growth work from both partners.
Compatibility in Communication
How couples communicate predicts relationship outcomes more than personality matching:
The Gottman Research
John Gottman's research identified communication patterns that predict divorce with over 90% accuracy:
The Four Horsemen:
- Criticism: Attacking character rather than behavior
- Contempt: Disrespect, mockery, eye-rolling
- Defensiveness: Refusing to take responsibility
- Stonewalling: Shutting down and withdrawing
Compatible couples aren't those who never conflict—they're those who repair ruptures effectively and maintain a 5:1 ratio of positive to negative interactions.
Conflict Styles
Couples can be compatible in different conflict styles:
- Validators: Calm, respectful problem-solvers
- Volatiles: Passionate arguers who also express love intensely
- Avoiders: Minimize conflict, emphasize shared values
All three styles can work if both partners share the same approach. Problems arise when styles clash (e.g., volatile + avoider).
Values Alignment
Core value compatibility predicts long-term success more than personality traits:
Critical Value Areas
- Children: Agreement on whether to have them and parenting approach
- Money: Spending vs. saving orientation, financial goals
- Religion/spirituality: Role of faith in daily life
- Family involvement: How much time with extended family
- Lifestyle: Urban vs. rural, adventure vs. stability
- Career priority: Balance of work and personal life
While some differences can be negotiated, fundamental misalignment in core values creates persistent friction.
Emotional Intelligence Compatibility
Partners with similar emotional intelligence levels tend to understand each other better:
- Emotional awareness: Ability to identify and name feelings
- Emotional expression: Comfort sharing feelings openly
- Emotion regulation: Managing intense feelings without destructive behavior
- Empathy: Understanding partner's emotional experience
Significant gaps in emotional intelligence create frustration—the more aware partner may feel burdened while the less aware partner may feel criticized.
Growth Orientation
Compatible couples share similar orientations toward personal growth:
- Both committed to learning and self-improvement
- Ability to give and receive feedback
- Willingness to work on the relationship
- Shared vision for the future
When one partner wants growth and the other is content, resentment builds. The growing partner feels held back; the content partner feels perpetually inadequate.
Practical Compatibility Factors
Beyond psychology, practical compatibility matters:
- Energy levels: Matching activity preferences and sleep schedules
- Cleanliness standards: Different tolerances create daily friction
- Social needs: How much time with others vs. as a couple
- Sexual compatibility: Frequency, preferences, attitudes
- Health habits: Diet, exercise, substance use
Compatibility Is Dynamic
Compatibility isn't static—it evolves as individuals grow. Sustainable relationships require:
- Growing together: Sharing experiences, learning together
- Maintaining individual growth: Supporting each other's personal development
- Adapting to change: Renegotiating as circumstances shift
- Continued investment: Dating, curiosity, appreciation
Many couples who were compatible initially drift apart; some who seemed incompatible grow toward each other. Compatibility is both a starting point and an ongoing practice.
The Compatibility Bottom Line
Research suggests the most important compatibility factors are:
- Shared values on major life decisions
- Secure attachment or commitment to developing it
- Similar communication styles and willingness to learn
- Matching growth orientation
- Emotional intelligence compatibility
Personality type, interests, and even initial chemistry matter less than these foundational factors. The best predictor of relationship success isn't finding a perfect match—it's finding someone committed to building a good relationship with you.