The belief there’s one singular human intrinsically and wholly compatible to you and you alone (and vice versa) is nice in theory. But thinking you’re in a relationship with your “soulmate” could be hindering you from maintaining a sex life you’re out-of-your-mind crazy about in the longterm, according to new research from the University of Toronto.

In the study, published in the Journal of Personality and Social Psychology, researchers took to literature and questioned 1,900 men and women from heterosexual and homosexual relationships. The team compared the beliefs of people who steadfastly trust in sexual destiny—those who figure sexual satisfaction is obtained by finding a compatible partner—versus those who believe in sexual growth—the idea sexual fulfillment comes from hard work and giving things the old college try. Spoiler alert: The latter is the secret to great sex for life.

When you find a “soulmate,” odds are good you stop trying and just expect sexual satisfaction and excellence. Sorry, that’s not the case. This “sexpectation,” the authors say, can undermine your relationship.

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“People who believe in sexual destiny are using their sex life as a barometer for how well their relationship is doing, and they believe problems in the bedroom equal problems in the relationship as a whole,” lead study author Jessica Maxwell, Ph.D., said in a press release. “Whereas people who believe in sexual growth not only believe they can work on their sexual problems, but they are not letting it affect their relationship satisfaction.”

You’ve heard of the honeymoon phase; everyone’s on their best behavior for the first couple months before things become a bit more real. Well, the same goes for sex. The bliss lasts for about two to three years before the desire starts to ebb and flow. But the benefit of believing in sexual growth is you’re both willing to put in the effort to maintain and nurture it—and get past rough patches.

And don’t just assume women are the ones pining after soulmates and believing in romanticized sexual destinies. Au contraire: The study found women are more likely to believe sex takes work in a long-term relationship than men are, probably because it takes more work for women to be satisfied in the sack.

Also note this isn’t black or white (more like 50 shades of grey): Some sexual-destiny believers are interested in tweaking their sex norms for the sake of their lover—but only under the pretense that person is their true soulmate.

Bottom line: Any issues you’re having during sex—you can’t get her off, you can’t climax, she’s not in the mood—are completely expected. It doesn’t mean your relationship is any less solid; it just means you have to work a bit harder to find the sweet spot (in more ways than one). See what other secrets happy couples in long-term relationships are harboring.

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