A friend who had just come out of a relationship of more than two years sat across from me and said something I hear all the time: “We always thought we were right for each other, until we realised we weren’t at all.”
When I asked what exactly hadn’t worked, she thought for a long time and came up with one word: “Chemistry.”
“Chemistry” is the most overrated word in modern relationships.
The link between the quality of a long-term relationship and that sense of “it just feels right” is far weaker than most people think. Chemistry can help you start a relationship, but it rarely helps you judge how far it can go. Leaving the question of compatibility to chemistry is a bit like making a major investment decision on gut instinct. Winning feels great, losing hurts, and when you look back you often find the warning signs were there from the start. Nobody had treated them as questions worth asking.
In IDO’s relationship strategy framework, we break compatibility down into four dimensions you can assess: values, attachment, intimacy intelligence and life direction. What these four have in common is that none of them is a mystery you’ll “just know when the time comes”. They’re concrete questions that can be answered honestly and discussed seriously. Once you’ve worked through them, compatibility stops being a vague feeling and becomes a decision you can weigh up rationally.
Values: the operating system of your relationship
When many people talk about values, they reduce it to “seeing the world the same way”, a grab bag of political views and taste in brands. That’s far too narrow.
The values that really matter in a relationship are your underlying judgements about what’s worth protecting, what’s worth investing in and what’s worth letting go. They include, among other things, how you define loyalty, where you draw the line on family obligations, what money means to you, and how you balance personal space with shared space. When a couple are out of step on these deeper judgements for a long time, everything from who does the dishes to whether to move cities becomes a sore point that keeps flaring up.
The Gottman Institute’s long-term research on marital stability found that 69% of couples’ conflicts are “perpetual problems”, rooted in deeper differences of values and personality rather than specific incidents that can be resolved. In other words, what you’re arguing about may not be what happened today. It may be that your two operating systems aren’t compatible.
So don’t let “we get on so well” stand in for “we’ve talked about our values”. It isn’t enough to talk about them. You need to see them, to watch how the other person’s underlying judgements play out under real pressure and in big decisions. What to do: write down three values you will never compromise on (for example, “no long distance, whatever happens” or “household finances must be transparent”). Ask the other person to write down three as well, then sit down and compare them. Look at how far apart you are and whether there’s room to negotiate, rather than assuming “time will sort it out”.
Attachment: not whether you love, but how you love
There’s already plenty of popular writing on attachment. The core idea fits in one sentence: your attachment style shapes not how deeply you love, but the form that love takes.
Attachment theory, developed by Bowlby and Ainsworth, tells us that the patterns of security we form in early relationships continue to shape our intimate relationships as adults. People with secure attachment find it easier to trust, express their needs and cope with distance. People with anxious attachment need repeated reassurance that “you’re still here”. People with avoidant attachment swing back and forth between closeness and independence, feeling smothered when things get close and longing for connection when there’s distance.
To judge whether two people are right for each other, it isn’t enough to ask whether someone is “a good person”. You need to look at whether your attachment patterns fit together and what your way of repairing after conflict looks like. When someone anxious meets someone avoidant, without awareness and the right tools they can easily get stuck in an endless cycle of pursuit and withdrawal. It isn’t that they don’t love each other. It’s that the forms their love takes keep treading on each other’s toes.
Here’s something anyone can do: first understand your own attachment pattern, then watch how the other person responds. When you express unease, is their first reaction to move closer or pull back? After a disagreement, who starts the repair, and how does it happen? These patterns of response predict the long-term quality of a relationship better than whether they’re “usually nice to me”.
If you find that your attachment pattern, or theirs, is turning the relationship into a source of recurring pain, it may not be a personality clash. It may be a pattern that needs to be recognised. Learning about it can help you grow, but if past trauma is affecting your day-to-day life, please seek help from a registered psychologist or qualified counsellor.
Intimacy intelligence: the overlooked language of relationships
Intimacy intelligence (relational intelligence in intimacy) isn’t about technique or frequency. It’s about whether a person can communicate with body and emotions at the same time, and whether they can keep talking and hold boundaries within intimacy.
This dimension needs to be on the table when we talk about compatibility because so many long-term relationships break down sexually, and it doesn’t start with “the spark has gone”. It starts with never having built a shared language for talking about sex in the first place. Two people can talk about everything else, yet when it comes to desire, preferences, frequency and shame, they’re left guessing. Over time, the silence becomes distance.
You don’t need to ask anything intrusive to gauge compatibility here. You can observe. In an intimate relationship, can this person express their needs honestly? Can they respect a no? Can they hold “let’s try it” and “I’m not really comfortable” in the same conversation? This isn’t about being “uninhibited”. It’s an adult’s awareness of their own body and emotions.
One useful question to reflect on: if something about sex made you feel vulnerable, would you dare to tell them? If you suspect they might avoid the subject, that “might” is itself a signal worth taking seriously.
Life direction: romance shouldn’t fight reality, or avoid it
Early in a relationship, many people deliberately play down one fact: you’re heading in a particular direction, and so is the other person.
Life direction (life trajectory) covers career plans, where you want to live, your responsibilities for ageing parents, whether and when to have children, and how you weigh risk against stability. These aren’t “conditions”. They’re the map each person is carrying along their own road. Whether two roads can run side by side, when they’ll need to merge, and whether the cost of merging is bearable: this is the step in assessing compatibility that comes closest to due diligence.
Most long-term relationships that don’t last aren’t wrecked by one sudden disaster. They’re worn down by the recurring thought “I thought you’d change”. One person wants to retire before 40 and sail around the world, while the other sees a steady income and an executive role as the source of their security. One person definitely wants children, while the other hasn’t made up their mind. None of these differences is right or wrong in itself, but pretending they don’t matter is a problem.
The action here is very specific. Before your relationship moves into commitment, lay out each of your life maps for the next five to ten years and go through them point by point. Where do they overlap, what needs negotiating, and where are the hard boundaries neither of you can compromise on? This isn’t the opposite of romance. It’s an honest prelude to long-term happiness.
From a vague “are we right for each other?” to a judgement you can answer
Back to my friend. If she had broken the relationship down along these four dimensions at the time, asking herself and her partner, she might have seen sooner that there was one hard conflict on values they could never get around, that their attachment patterns kept triggering the same hurt, and that the conversations about intimacy and life direction had never really happened. She wouldn’t have traded two years of “chemistry” for that conclusion.
Breaking compatibility down isn’t about killing romance. Quite the opposite. Serious people deserve a sturdier kind of romance: a long-term relationship that two people build together, not through luck or settling, but through clear-eyed choices and ongoing care.
If you’re in a relationship and unsure whether you’re right for each other, or you want to get clear on these dimensions before your next relationship, book a relationship consultation with IDO. We won’t make the decision for you, but we can help you turn “a vague feeling” into “questions you can answer”. After all, long-term happiness has never been a gamble. It comes from understanding each other and working at it.
References
- Gottman, J. M., & Silver, N. (2015). The Seven Principles for Making Marriage Work. Harmony Books. (Research on perpetual conflict and differences in values)
- Bowlby, J. (1969). Attachment and Loss, Vol. 1: Attachment. Basic Books.
- Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. (1978). Patterns of Attachment: A Psychological Study of the Strange Situation. Lawrence Erlbaum.
