Why elderly men were more likely to be married and living with their spouses than elderly women?

it is reported that "Women Have Lower Income in Retirement than Men -- And Thus Higher Poverty. In 1997, median income for elderly unmarried women (widowed, divorced, separated, and never married) was $11,161, compared with $14,769 for elderly unmarried men and $29,278 for elderly married couples. Thus, the poverty rate for elderly women was higher than that of men: in 1997, the poverty rate of elderly women was 13.1 percent, compared to 7.0 percent among men. Among unmarried elderly women, the poverty rate was significantly higher -- about 19 percent. " It is also said that in America, there is as twice women live alone as men. However, the Cencus Bureau estimated that "elderly men were nearly twice as likely to be married and living with their spouses as elderly women do( 75% versus 41%). Is that only because of emotional reason? Well it is hard to say. From the economic point of view, poor couple will get lower social security. If so, why those elderly men want to marry elderly women? It may be better for them to stay alone to get much highter social security rather than getting married.I feel confused about that. Could you give me some explanations please.