Sorry, but you're superimposing myth into history.
I remember one specific poster who, I think like a lot of contemporary Mormons plus their allies, assumed that there was some glut of widowed women and that therefore, men just had to step up and marry them as a plural wife.
According to the Changing World of Mormonism, pp. 224-225: [LDS} "Apostle John A. Widtsoe, who was born during the polygamy years (early 1870s) stated:
We do not understand why the Lord commanded the practice of plural marriage. (Evidences and Reconciliations, 1960, p.393). One of the most popular explanations is that the church practiced polygamy because there was a surplus of women. The truth is, however, that there were less women than men. Apostle Widtsoe admitted that there was no surplus of women: 'The implied assumption in this theory, that there have been more female than male members in the Church, is not supported by existing evidence. On the contrary, there seems always to have been more males than females in the Church... The United States census records from 1850 to 1940, and all available Church records, uniformly show a preponderance of males in Utah, and in the Church. Indeed, the excess in Utah has usually been larger than for the whole United States, ... there was no surplus of women' (Widtsoe, Evidences and Reconciliations, 1960, pp.390-92," as cited in Changing World, pp. 224-225).
Already beat ya to it, one post above :p.