"Were we disposed to define more specifically the conditions necessary to secure the most harmonious matrimonial unions, it would be useless to do so; for unions of this sort never have been, and never will be-with rare exceptions-formed in accordance with a prescribed method independent of any emotional bias. Nor is it probable that such a plan would result in remedying, in any appreciable degree, existing evils. It is a fact too patent to be ignored that a very large share of the unhappiness in the world arises from ill-mated marriages; but it is also true that nearly the whole of this unhappiness might be averted if the parties themselves would endeavor to lessen the differences between them by mutual approximation."