This'll be controversial...

Some can’t be satisfied: multiple partners points to marriage misery for women, researchers say | The Australian

The Huffington Post has a lengthier article on the study, which includes some somewhat skeptical takes:

"There are a wide variety of reasons that may lead people to have multiple partners before marriage and, independent of how many partners they have, also be less satisfied in marriage," Dr. Jim McNulty, a social psychology professor from Florida State University who has published a plethora of research on the topic, wrote in an email.

"For example, people who tend to avoid commitment in general may have more
sexual partners and be less happy when they settle down. It’s not the fact that they have more sexual partners that leads them to be less happy, it’s the fact that they don’t really like commitment. I would be very surprised if having multiple sexual partners before
marriage, independent of any other factor, has a direct causal influence."

In other words, correlation should never be confused with causation.

"We cannot make any conclusions about cause-and-effect," says Justin Lehmiller,
PhD, sex educator and researcher at Purdue University, adding, "Could it be that multiple premarital partners impacts marital happiness? Maybe. But it could also be that people who have more partners have different personalities or different attitudes toward marriage or relationships."

That point about causation may well be right, but nonetheless, if the study is correct, doesn't it indicate that men should legitimately be cautious about marrying a woman who has many partners (and be increasingly cautious the more she has had?)