It’s turning out to be a schadenfreude kind of summer.

No, that doesn’t mean damp beyond endurance. Schadenfreude is German for “joy at the suffering of others.” And if that’s not the exact emotion “Gigli” is inspiring in every American except those who own stock in Sony Pictures, I’m Martha Stewart.

Who, by the way, is another font of national schadenfreude. As is William (“I’m So Busy Being Virtuous I Forgot to Tell You I’m a Compulsive Gambler”) Bennett. And also Mike (“I Went Broke on $300 Million”) Tyson. And even Kobe Bryant, the erstwhile golden boy who, at the very least, committed adultery and then had the chutzpah to dub it a “mistake” — as if he’d been caught putting a Coke can in the garbage instead of recycling.

To complete the schadenfreude souffle, we have Ben Affleck and Jennifer Lopez themselves. Not only are these super-rich, super-beautiful superstars stuck with a bona fide Butterball, now they’re also dealing with the fact that Ben just may have been cavorting — that’s the polite word — with strippers (another polite word). When? On the exact same night that J.Lo was on TV burbling about their love. It’s just too juicy!

But why? Why the secret spasms of glee we feel at such tsuris? It’s not that we actively wished any of these people ill. (Except Mike, for being a rapist.) But now that ill has arrived, we’re handing it a beer.

Are we that shallow? Sadistic? Envious? Are our lives so pathetic that we can enjoy them only when we remind ourselves, “Well, at least I’m not facing eight to 10 like a certain doyenne of domesticity I know”?

Take heart, my fellow schadenfreuders: Psychologists are hypothesizing that this feeling is not evil, only human. “When you find something that is universal in people, like enjoying the taste of sweet food” — or the suffering of others — “you’re plugging into a part of human nature,” says Professor Frank McAndrew of Illinois’ Knox College.

Evolutionary psychologists like McAndrew believe that human nature evolved by holding onto the traits that kept us alive. For instance: Our sweet tooth meant we spat out many bitter poisonous plants.

But how on earth did schadenfreude keep us alive? By making us long to live to see another day of the O.J. Simpson trial?

No, it’s more practical than that. It really boils down to learning information about your rival’s weakness.

“For most of the 3 million years we were evolving, we lived in little groups of humans,” explains McAndrew. “You knew everything about everyone in your group” — especially the top banana. “If I was a caveman and I wanted to climb the social ladder, I had to keep my eye on him. What did I want to know about him? Anything that I could exploit. So if I find out that he’s broken his leg or just had a falling out with his wife, that’s valuable.”

A limping leader can be beaten up. A miffed mate may want to switch partners and mate with me! So we survived — and thrived — by getting the scoop on our rivals.

But J.Lo and Ben aren’t our rivals, right? I mean, unless we happen to be Julia Roberts or Keanu Reeves?

Ah, but your mind thinks they are, says McAndrew. Thanks to constant celebrity coverage, “We know so many intimate details about them, it sort of tricks us psychologically. We react to them as if they are important people in our lives.”

And when bad things happen to them, we rejoice. Our rivals have been routed. As one friend said to me: “If J.Lo dumps Ben, that means I can still get him!”

And next summer we’ll be reading about you. I can’t wait!