Power and the Cost of Leaving

Whoever can do without the other is the stronger one.

— Folk wisdom

One partner says: “If you don’t like it, leave.” The line looks emotional, but its force is produced by accounting. The apartment is in the speaker’s name. The job and the friends are in the speaker’s city. The other one moved, spent several years with the children and lost professional contacts. The door is physically shared. The cost of walking through it is not. The folk formula calls this asymmetry love: whoever loves less is stronger. The observation is sharp, but the formula measures the wrong variable.

The price of disagreement

Bargaining starts with outside options — what each person can get away from the union. A couple creates a joint surplus — a home, childcare, closeness, savings on resources — but each share depends on what happens if they fail to agree. One can move into an apartment of their own and keep their income; the other loses housing, status and a familiar network. A workable option outside the union makes refusal more credible and increases influence over how the joint surplus is divided.

Feelings affect the cost of a breakup, but they do not exhaust it. You can love equally and have different alternatives. You can love more and still hold the income, the housing and the support. You can be emotionally cold and fully dependent financially. The “love less” formula tries to change one component of the cost of leaving and leaves the rest where it was.

The pie and the share are two different problems

Bargaining often mixes up creating the joint surplus and splitting it. A couple can pick an arrangement that makes both richer than living alone, and then divide the gain very unequally. The reverse also happens: fighting for an equal share can shrink the surplus itself. Formal bargaining theory keeps the two quantities apart: the set of possible agreements shows what the parties can build together, and the disagreement point shows where each of them starts if the agreement falls through.

This is how a good relationship with a bad distribution appears. Living together gives both warmth, children, status and savings, but one gets more free time and career growth, and the other gets more unpaid work. As long as an immediate breakup is worse for both, the arrangement can be stable. Stability tells you that nobody left; fairness does not follow from it.

Raising total welfare does not automatically strengthen both. If one partner fully controls the new income, the common pie grows while the other’s disagreement point barely moves. Turning part of the gain into joint property, personal income and portable skills raises both the total result and the ability to negotiate without threats.

Investments that lose value outside the door

Dependence is created above all by specific investments — valuable inside a particular union and hard to carry outside it. One partner learns the other’s language and moves. The other keeps building a career. One takes over the childcare so the other can work more. The joint system can become more efficient. But when it breaks up, one person’s career capital stays with them, and years of housework cannot be sold to the next employer. This is the classic problem of renegotiation after an irreversible investment. While the parties are still bargaining before the investment, a promise to share the future gain sounds convincing. Once the investment is made and cannot be undone, the balance shifts. The partner with the better outside options can reopen the terms.

You do not have to suspect every division of labour of future betrayal. It is enough to see the structure of the risk. Good intentions today do not guarantee equal bargaining power in ten years.

Suppose the dependent partner reads the advice and starts performing less involvement. He answers later, hides his feelings, threatens to leave. If the threat is not credible, bargaining power does not change. The other one still knows about the apartment, the income, the children and the residence status. Theatrical coldness does not create an outside option. And if the strategy does succeed in destroying closeness, the joint surplus shrinks. The couple divides a smaller pie. A player can get a slightly larger share and still end up poorer in absolute terms. This is the central error in adversarial advice. It treats bargaining power as the final goal and the relationship as a fixed resource. But power inside a union and the value of that union move independently. Gaining leverage can reduce the value of the thing you have leverage over.

The model does not ask anyone to pretend that emotions do not matter. Strong attachment really does raise the subjective cost of leaving. If one partner feels that life without the other is impossible, his disagreement point is low even on a good income. But emotional dependence is not driven by the strength of love alone either. It is shaped by social isolation, experience of violence, self-worth, access to support and the ability to imagine a life after the breakup. Again the formula collapses a whole system into a single feeling. Caryl Rusbult’s investment model describes commitment through satisfaction with the relationship, the quality of alternatives and the size of the investments. Large investments can hold together a good union and a bad one alike. Weak alternatives strengthen attachment to the current state without making it any better.

Changes in outside options have observable consequences before any breakup. The extension of alimony rights to cohabiting couples in Brazil has been used as a quasi-experiment: in families that stayed together, women’s working hours and investment in children’s education changed. That is consistent with a stronger outside option for women, but it does not measure bargaining power directly. In the United States, unilateral divorce reforms were likewise linked to measures of family distress. Both designs show that a legal position in the event of exit can change decisions inside an ongoing union, without turning “power” into something you can observe directly.

The claim “he stays, so he loves her” is unreliable too. Sometimes people stay because leaving is too expensive.

Bargaining power is strengthened by your own income, maintained qualifications, legal clarity, social ties and a realistic ability to live separately. If one partner makes specific investments, they can be offset by joint property, pension savings, access to money, a marriage contract, a division of care work and support for going back into the profession. Such measures are sometimes read as a lack of trust. But trust does not require making one person hostage to the other’s goodwill. If anything, a union where both are able to leave and stay anyway says more about the quality of the relationship.

The cost of leaving does not have to be zero. Shared children, a shared home and a shared history inevitably create connection. The task is not to let one person accumulate all the irreversibility; an easy breakup is not a goal in itself. Whoever loves less is not necessarily stronger. The stronger one is whoever can afford to disagree. That conclusion is less romantic, but it can be changed: you can lower the price of disagreement without lowering the love.

Power that does not look like power

Bargaining power is made of feelings and of readiness to leave. Money, housing, citizenship, a professional network, control over information and the ability to sit calmly through a conflict also change the price of disagreement. A couple that looks equal from outside can live in a very unequal regime if a breakup means pain for one and the immediate loss of home, income, status and social environment for the other. The formal right to say no means little when the consequences of that word are catastrophic.

There are quieter sources of influence. Whoever understands the finances, the paperwork, the family logistics or the medicine better gradually turns into a ministry with a lifetime appointment. Sometimes power goes not to the most competent but to the least reliable: the family builds backup plans around his lateness, his blow-ups and his disappearances, and as a result he carries fewer obligations precisely because everyone else is used to rescuing the system. Power can feel less like an order and more like chronic exhaustion in one person and chronic freedom in the other.

The stability of a union depends not on perfect equality of resources, which is nearly unattainable, but on limits placed on advantage. A person can be in a position to dictate terms and choose not to use it fully. Your own income, your friends, your skills and the ability to live alone protect the voluntary part; they do not threaten love. Someone with somewhere to go stays by choice rather than because the door is locked.

Love explains why people want to be together. Power sets the terms on which that happens. Asymmetry becomes a problem when it is made invisible and permanent, releasing one person from having to account for the price the other one pays.

Main sources

Rusbult, C. E. (1983). A longitudinal test of the investment model. Journal of Personality and Social Psychology, 45(1), 101–117.

Lundberg, S., & Pollak, R. A. (1996). Bargaining and distribution in marriage. Journal of Economic Perspectives, 10(4), 139–158.

Nash, J. F. (1950). The bargaining problem. Econometrica, 18(2), 155–162.

Rangel, M. A. (2006). Alimony rights and intrahousehold allocation of resources: Evidence from Brazil. Economic Journal, 116(513), 627–658; Stevenson, B., & Wolfers, J. (2006). Bargaining in the shadow of the law: Divorce laws and family distress. Quarterly Journal of Economics, 121(1), 267–288.