Why relationships that "should" work sometimes don't

Couples often come into a relationship, or into therapy, with a puzzling question: on paper, everything fits, so why does it feel so hard? Or the reverse: the connection feels undeniable, so why does the relationship keep hitting the same walls? A useful way to make sense of this is to look at relationships along three distinct dimensions — chemistry, compatibility, and commitment — because a relationship can be strong on one or two of these and still struggle badly on the other.

Chemistry

Chemistry is the felt sense of connection and attraction between two people — the ease, the spark, the pull toward each other. It's often what draws people together in the first place, and it plays a real role in what keeps a relationship feeling alive over time. But chemistry alone answers the question "does this feel good?" — it doesn't answer "can this last?" or "can we build a life together?" Relationships with strong chemistry and little else in place often burn intensely and then struggle once the initial pull settles into daily reality.

Compatibility

Compatibility concerns whether two people's values, habits, communication styles, and life goals genuinely fit together — not identically, but workably. This is where much of the practical texture of a relationship lives:

• How each partner communicates under stress, and whether those styles clash or complement each other
• Whether core values around money, family, faith, ambition, and lifestyle are aligned closely enough to build a shared life
• Whether day-to-day habits and rhythms — around time, tidiness, socialising, conflict — are manageable for both people over the long run
• Whether each partner's underlying needs (for closeness, independence, structure, spontaneity) can realistically be met by the other

Commitment

Commitment is the deliberate choice to stay, invest, and build with a particular person — distinct from how connected or well-matched the couple feels in a given moment. It shows up as follow-through: prioritising the relationship in practice, not just in feeling; repairing after conflict rather than withdrawing; and maintaining the relationship through periods when chemistry is lower or compatibility is being actively tested. Commitment is what allows a relationship to survive the inevitable stretches where the other two dimensions are under strain.

Why one or two dimensions is often not enough

• Chemistry without compatibility or commitment tends to produce relationships that feel intense but unstable — strong pull, frequent conflict, difficulty building anything durable.
• Compatibility without chemistry can produce relationships that function well on paper but feel flat or under-nourished — partners who cooperate effectively but don't feel deeply drawn to each other.
• Commitment without chemistry or compatibility can sustain a relationship's structure while leaving both partners feeling unfulfilled inside it — together, but not really connecting.
• Any two dimensions without the third eventually puts real strain on a relationship, because each dimension is compensating for a genuine gap rather than the relationship being fully supported across all three.

How this framework is used clinically

This three-dimensional view sits behind a structured approach used in couple therapy: rather than treating "we're not getting along" as a single, undifferentiated problem, each dimension is assessed somewhat separately, often alongside a related model of relationship functioning — Relationship Ability (the skills each partner brings to relating well), Relationship Skills (how those skills are applied in practice, day to day), and Relationship Knowledge (each partner's understanding of the other, and of what the relationship actually needs to thrive). Together, these give a clearer picture of exactly where a relationship is growing, where it's become stuck, and which specific area — chemistry, compatibility, or commitment — most needs attention.

This matters because couples often intuitively sense that "something is missing" without being able to name which dimension it is — and the right kind of support looks quite different depending on the answer. A couple missing chemistry needs something different from a couple missing compatibility, which is different again from a couple whose commitment has quietly eroded. Naming the actual gap is usually what makes it possible to close it.