Abi, 25, had been dating her now-boyfriend for a fortnight when he started saying weird things during sex.
"It was just like, little whispers," she remembers. "Throughout sex. He thought I couldn't hear it. It was very psychotic."
What obscene phrase did Abi's boyfriend feel compelled to mutter beneath his breath? The worst kind of three-word phrase, obviously.
I love you.
Given that they didn't live in the same state, weren't exclusively dating yet, and had only been on a handful of dates, understandably Abi's boyfriend's love-feelings were privileged information, not ready to be publicly shared.
"I was freaked out," Abi says of her emotions at the time. "I wasn't sure how I felt about him."
Happily, as it turns out, Abi's boyfriend wasn't just a random love-declaring creep—he actually did love her, and wanted her to know it. "I called him out on the whisper thing, and he admitted he wanted me to hear it," she remembers. "He told me he'd loved me since I met him!"
This is all very cute, but for the most part "I love yous" tossed out during sex are disposable, like condoms limply flung in the trash. But why might we feel the urge to tell someone we love them just because we currently happen to be slobbering on their genitals?
"It's in the cultural script," explains Dr. Daniel J. Kruger of the University of Michigan, a psychologist with a particular expertise in the post-coital time interval (a.k.a. the interval post-fucking where you make polite small talk before ordering an Uber). "It's what people are supposed to say when they're having sex with someone."
"It's as if there's a social pressure on people I've had sex with," agrees Domina Elle, a Denver-based dominatrix and self-described energy alchemist. "It's not that they're lying, more like there's a social pressure on people to have an emotional bond with someone you're having sex with. As if they struggle with giving themselves permission to be sexual without a relationship."
"There's this Western, European-originating construction of romantic life that derives from the medieval knights searching for women in a town they can never reach," Kruger agrees.
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But the urge to blurt out your feelings—even if you only necessarily feel that way for all of ten seconds after climax—is also down to the complex architecture of the human brain.
"When people have sex, this creates a whole cascade of neurotransmitters," Kruger explains. "The effect on the brain is similar to the substances people take recreationally. The endogenous opioid system is activated in a similar way to when you're in a state of elation or after you've had some really good exercise. So basically, in that moment, you might actually feel it, right? You might actually feel it. It's like when someone is addicted to a substance like heroin or cocaine. When you're in that moment of bliss, it's all [you] can experience."
Exactly like heroin or cocaine, love is a fun, often damaging drug that ruins your figure (worn-out couples, tired of fucking, always turn to food.) And just like drugs, you may feel things that aren't real as your brain sparks up like an overloaded extension board at a Yayoi Kusama exhibit.
"I'd have loads of hot hate sex with Anwar*," Vanessa, 29, tells me. "I'd get it into my mind that I felt deeply for him, that I was feeling the early crackle and glimmer of fuzzy phase one love, but then I'd snap out of it and realize it was just sexual."
"When you're in the middle of sex and your partner says 'I love you,' the sex may be better," explains Professor Aaron Ben-Ze'ev, a moral philosopher specializing in the study of human emotions. "So men and women can take advantage of it for its practical value in increasing sexual desire on both sides."
Anecdotally, this matches up with what I've heard from my friends and peer group throughout our collectively ignominious sexual histories. After all, the hottest things to say in bed are the filthiest, and what could be more taboo that saying "I love you?" Only suckers for the late-capitalist wedding industrial complex actually believe in romance—for the rest of us it's just a filthy fetish, like wipe-clean puffa jacket porn and specialist adult breastfeeding sites.
But is this so bad? Let's have the moral philosopher answer that one, shall we?
"Morally, it is wrong to lie to gain something for yourself," Professor Ben-Ze'ev confirms. "If you're saying 'I love you' during sex with the intent of only benefiting yourself, that's immoral. You could say something like, 'you're so beautiful', or 'you're so sexy,' or things like this. These kind of white lies are very fine."
(Also, men are more likely to field these compliments when it comes to love and sex. One 2012 study found that a man who says "I love you" to a woman before doing the sex with her is probably only doing it to do the sex with her, if you catch my drift.)
Of course, you might actually feel like you love the moron you're cresting mid-coitus on a splendid, orgasmic wave. Remember, these feelings are false, but go ahead and suspend disbelief for a bit if it'll help you get off. Also, stuff you say on drugs doesn't count.
"When I'm really high I'll say 'I love you' when I know that my mind and body really meant something along the lines of, 'I love it,'" says Chloe, 28. "I don't even try to clarify it unless my partner explicitly tells me they're freaked out. Because, whatever, it's just love, you know?"
And if having a buzzed Chloe make mangled professions of love is a huge turn-off, she says she's totally chill about it.
"One man was once like, 'It stresses me out,' and I was like, 'OK, then don't have sex with me.' I got [other] people on deck."