If we have been baptized and received our endowment, the next step along the path would be to participate in the ordinance of celestial marriage. The longer one remains single, the less available are potential spouses of similar age. This is the one that used to keep me up at night. Marriage is urgent because, as you grow older, there are fewer individuals of marriageable age from whom to choose. The biological clock keeps ticking for men and women.
Parenthood requires energy and time.
Marriage is urgent because it's tough to have the energy you need to have teenagers at home when you're in your eighties. This is the happiest reason of all. Being married is simply a better way to live. Because there's something better. It's no good to be married just for the sake of being married, though.