The Drake Equation... of Love

The Drake Equation is a research tool designed to make educated guesses for one of science's most elusive questions: Is there intelligent life on other worlds? It works like so: You take the number of stars in a certain population (the galaxy, for example), multiply that by the fraction of stars which have planets, then multiply that by the average number of planets per star where conditions are right for life, then that by the probability that, given conditions, life will emerge, etc., etc., etc., until you multiply everything out and find out how many civilizations there are in the galaxy.

So, in a bout of moping and self-pity, I decided to turn Drake's method on another, far more elusive question: Will I ever find true love? I came up with this equation to determine the number of relationships I could expect to have over the course of my lifetime:

Np = The number of men/women you typically meet in a year
fs = The fraction of men/women whose sexual orientation involves dating a member of your sex
fa = The fraction of men/women who are available
ft = The fraction of men/women who you would consider "your type"
pd = The chance, given that someone meets the above criteria, that you will actually wind up dating them at least once
pr = The chance, given that you date a person once, that you will become involved in an actual relationship with them

N = Np fs fa ft pd pr
= The number of relationships you can expect to have in a year