There are more than... 5,000 species of mammals of which we are one, but the percentage of mammals that have anything resembling a pair-bonded, long-term mating strategy, it's about 3-5%. It's extremely rare. And even our closest primate relatives, the chimpanzees, they don't have a long-term mating strategy.

Kinsey estimated 26% of married women committed an infidelity at some point during their marriage and about 50% of men. Other studies have given lower figures...

If you look at first marriage, second marriage, third marriage, as people get divorced and remarried, average age gap is, in America anyway, 3 years at first marriage with the guys being older, 5 years at second marriage, and 8 years at third marriage. That is, as men are getting older and getting divorced and remarry, they are marrying women who are increasingly younger than they are.

It has been reported, although Tinder denies this, it's been reported that something like 30% of the men on Tinder are either married or in long-term committed relationships, and they're looking for something on the side.

What people look for in a long-term committed mateship, like a marriage partner or a long-term romantic relationship, is different from what people look for in a hook-up or casual sex or one-night stand or even a brief affair.

Successful deception is facilitated by self-deception. So, if you really believe in X, then you're going to be a more successful salesman to convince other people of X. So, if you believe you're, let's say, a 10 in mate value, and you truly believe it, even if you're not, I'm going to have a more successful time convincing you that I am as well. And so, the hypothesis is basically that people self-deceive in order to increase the effectiveness of actual deception.

Women, more than men, prioritize good earning capacity, slightly older age, and the qualities associated with resource acquisition.

One of the hallmarks of emotional instability is how they respond to stress. So, emotionally unstable people tend to have a long latency to return to baseline after a stressful event.

Something like 28-30% of all people who are married will experience intimate partner violence in their relationship. So, it's not a trivial percentage.