The statistical description of the formation of marriages is hampered by the fact that the intensity of marriage of one sex depends on the available supply of potential spouses from the other. Unlike the situation that occurs in the study of fertility, there is no reason to give a preference to either of the sexes. To address the fundamental problem caused by the two-sex nature of the process, a solution is proposed that considers the sexes jointly. The solution relies on a novel use of generalized averages. The model is formulated in stochastic terms, and it is parametrized in terms of the overall level of nuptiality, the relative propensity of nuptiality by age, and the mutual relative attraction of spouses at different ages. Although national statistics collection relies on data aggregated by age groups, the models are formulated at individual levels to show how estimation could also be carried out in small populations. In particular, examples of how maximum likelihood estimation can be carried out are given for specific parametric models. The methods are illustrated by both monthly and annual nuptiality data from Finland.