This goes against the premise of every single romance novel, but you’re not going to marry the best sex of your life. At least, not if you’re like most women.

According to a recent study by iVillage, less than half of wedded women married the person who was the best sex of their lives (52 percent say that was an ex.) In fact, 66 percent would rather read a book, watch a movie or take a nap than sleep with a spouse.

Amanda Chatel, a 33-year-old writer from the East Village, says, “With the men I’ve loved, the sex has been good, sometimes great, but never ‘best.’ It’s resulted in many orgasms and was fun but, comparatively speaking, it didn’t have that intensity that comes with the ‘best’ sex.

“I knew [my best sex partner] was temporary, and so the great sex was the best because the sex was the relationship,” she adds. “We didn’t have to invest in anything else.”

Knowing something is in scarce supply enhances desire, and that’s difficult to do in a marriage. You can’t really tell your partner that you’re going out for groceries and may never come back. Well, not if you want any semblance of the stability that generally defines marriages.

Chatel also admits, “We tend to remember things better than they actually were because we no longer have them.”

That might explain why such a variety of women recall having passionate sex in the hallway of someone’s apartment, but forget that they had to have sex in the hallway because he had four roommates and slept on a futon.

A 36-year-old marketing executive from Chelsea we’ll call Abby says that “what makes sex incredible, or places it into the range of ‘best sex’, is an element of danger. There’s an element of disobedience . . . that elicits a feeling of carnal desperation. [That feeling is often provoked by] the guy who you shouldn’t be with versus the one that you marry.”

And Noel Biderman, CEO of Ashley Madison, the site that promotes extramarital affairs, claims that the best sex is defined as something that, for many, encompasses “danger, newness and fantasy fulfillment.”

That’s only sensible. While feelings of danger might be thrilling while you’re having carnal knowledge in an abandoned alleyway, they’re not so great when you have to get kids ready for school.

Sex therapist Sari Cooper says many women come to her troubled that their husbands aren’t ideal sexual partners.

“Your best sexual relationship has likely been with the person who was most unstable and most volatile, but was very passionate,” Cooper says. “That’s like riding a roller coaster. That’s passion. But if you have a family, riding a roller coaster isn’t that great for kids.”

If that’s the case, you have to find someone where the relationship is more of a gentle carousel motion. No kids ever got sick from that.

A 36-year-old actress from Greenpoint, Brooklyn, we’ll call Jane says sex with her husband “is not, overall, the hottest sex of my life. But I wouldn’t trade it for a second to have the giver of the hottest sex be my life partner!”

As we grow up, hot and sweaty takes a back seat to kind and sweet.

“I used to swear that I’d take the best sex over the love stuff any day, but recently I’ve realized that phenomenal sex will never hold a candle to real love and a healthy relationship,” Chatel says. “I fear I may have matured.”