Or don't. Here's a TL;DR: It's a relatively small effect where men tend to go for women more attractive than they are, and women tend to go for men who have higher status and earnings than they do.

Certain circles like to misrepresent it as responsible for why so many men remain single, but in reality people tend to match with those close to them in social status and earnings, with just a bit of the bias remaining unexplained by wage inequality.