Frederick Mosteller, if one wishes to make a good decision about whom to marry, it's as easy as simple division.
First the hard part: determine your total dating pool. Next, divide that number by the base of the natural logarithm (about 2.72) and marry the next best candidate that comes along. This puts your chances of having chosen the best candidate in the entire dating pool at 37%, or roughly 3 chances in 8 trials.
For example, if your estimated dating pool contained 272 distinct individuals, then your magic number would be 100. Date 100 people and having rejected all of them, pick the next one that seems better than all previous dating partners.