Gale-Shapely
A visualization of the Gale-Shapely algorithm. The men are below, the women are above.
All of the women prefer the man in the bottom left corner least. So he is repeatedly usurped until relegated to his least preferred woman, the top middle. Now get creative with generative algorithms. Generate a random preference list for each man and woman.
The execution slows down as the number of available partners decreases. The men selected later typically propose to more women, in order of decreasing preference.