Worldwide (citation needed but exists), women leave men at a higher rate when the last born child reaches 5 years old. Regardless of culture, religion, or other factors. The theory was that genetically that is when the child can gather it's own food and walk around and there is something genetic about it.
I'm sorry, but this is nonsense, you cannot use statistical inference in something like this, because the world is too small, and the factors too many. When you say "regardless of other factors" you have no idea how bad that sounds. "Other factors" considered by the survey, maybe, not in the real world. A single unkown factor, like intelligence of the father, or what the parents like to do on weekends, or relationships between jobs, can completely skew this thing one way or the other.
Also, the theory makes sense only to the extent of primates. Human beings maintain social status in a variety of ways, so the child reaching age 5 does not really mean much on its own. And yes we do have instincts to care for our offspring's welfare even when they are adults. I think it's more about people getting bored with each other, whether or not they have kids. Other studies have shown this too. The magic number is 4 years.
I never did the club hunting thing.
You didn't miss out on much. There are some great people who go clubbing to dance..etc with their friends. Very few 'nice' girls go to clubs to get picked up. They don't have to, and they don't want to. I've been approached by women in clubs, every half decent guy has.. and those women were always garbage. Or on a rebound. That sounds mean, but I'd be lying if I told you otherwise. And I live in DC so we party a lot.
But (in my experience), you still have to know them well- the anonymous stuff never worked for me. Too cold.
Congratulations, you are a decent human being who actually has feelings. Please collect your badge at the door, or pick up a free t-shirt from the table near the exit.