These tables, compiled from information published by the US Census Bureau, show the proportion of American men and women by age group and marital status. "NM" means never married, "Single" includes never married, divorced, and widowed. Numbers given are in thousands. The difference between the numbers of men and women in each category is shaded in pink where there are more men (theoretically favoring women) and blue where there are more women (theoretically favoring men). Note that people in long-term relationships but are not married are still counted as single, so if we posit that the demographics of unmarried partners are comparable to those of married partners, it's fair to conclude that percent difference column would be larger (in both directions) if only single people  without long-term partners were counted.

In the first chart, note that single men outnumber single women in the younger age groups, by about 6:5 in the early 30s. This can be attributed in part to birth rates that slightly favor boys, but more to the societal norm of the man being the older partner in the majority of relationships. The difference evens out and then reverses itself in middle age and beyond, with single women outnumbering single men by 2:1 and higher in the retirement years. The aforementioned societal norm plays a part here, along with the tendency for women to outlive men in old age.

The second chart shows the age differences between married partners. In most cases, the difference is not more than a few years. Where an age difference of at least two years exists, marriages where the man is older outnumber those where the woman is older by at least 3:1, and when the age difference approaches 20 years, that proportion is closer to 6:1.