Burdett and Celee (2001) present a model in which individuals can invest in their \"charm\" in order to Change their marriage class. The model suggests two equilibria, either everyone self-improves or nobody self-improves.Individuals do not take into account that self-improvement creates utility for a future partner and thus an underinvest- ment externality may arise.Self improvement can give rise to a desertion externality. People who before selfimprovement would have been accept- able partners may now be rejected by selfirnprovers. The Scottish equilibrium induces social welfare losses due to desertion externalities