->''"It's like a disease. I slept with Robin one time and I caught feelings. I caught feelings bad!"''
-->-- '''Barney Stinson''', ''Series/HowIMetYourMother''

Back before the sexual revolution, men and women could have sex if they were married or... well, that was pretty much the only way.

Okay, okay. Truthfully, premarital and extramarital sex have been occurring pretty much since marriage was invented. But it was looked upon with scorn, and often treated as though it didn't exist.

Even more truthfully, until the 19th/20th century, marriage was for considerations of status, wealth or power, and progeny (for anyone you're likely to read about, anyway. This may be one of those cases in history where it may be better to be poor -- ordinary people were more usually in love at least at the start of their marriage; they may also have been less likely to be virgins, though records of their lives are so sketchy it's quite hard to gauge what were the norms). For love or sex-for-the-fun-of-it one could have a mistress, only the Church vociferously frowned upon extra-marital sex. Love within the marriage was considered a lucky bonus, if it grew there (and it probably didn't)

Still, sex was seen as a sacred and special thing, so people still refused to have a physical relationship ''unless'' love (or at least the need to produce an heir) was involved, and doing it within a marriage was still the rule. Then, the unthinkable (or maybe just long-dreaded) happened: Some [[StrawmanPolitical flag-burning liberals]] acted as if it were OK to have sex JustForFun! No Strings Attached!

This cultural shift in the morality of sexuality was a reaction to the technological invention of the birth control pill, which gave women substantially more control over pregnancy than [[ButWeUsedACondom condoms]] offered. Secure from the possibility of being saddled with a kid born out of wedlock for the rest of their lives (which culturally back then was considered way worse than it is today) from the events of one brief coupling, women could afford to be freer with sex. Which meant [[TheSixties a lot of love for everyone!]]

However, [[ExecutiveMeddling TV executives]] were fearful of what {{Media Watchdog}}s and MoralGuardians would say about that, and thus a trope was born, described herein:

* If a man and a woman have a sexual relationship that is not based on love, one of them will fall in love with the other.
* First addendum: If the man is a conservative, it will be he. If he is a liberal, it will be either the woman or his partner.
* Second addendum: The partner who is in love will demand fidelity from the other partner.

Curiously, on [[EthicalSlut the flip side,]] some people view premarital or even casual sex itself as a blameless and pure act, with no negative consequences or moral stigma attached. This is considered either a symptom of the liberation of the human race from unnecessary complications and hang-ups, a depressing consequence of the modern tendency to view everything physical as without consequence and everything non-physical as without value, [[TakeAThirdOption or a little bit of both]].

Oddly enough, even open-minded fandoms fall prey to this. An earmark of the more obsessive [[{{Shipping}} shippers]] is no such thing as casual relationships/ dating/sex.

* If a man and a woman have sex, theirs will be considered by shippers the OneTruePairing.
* Most couples who start a relationship based only on sex will end up in a romantic relationship.

Still more often, there is a tendency among fandom to look upon ''any'' sex in a given series or film as cheap FanService, preferring to keep their relationships relegated to {{Subtext}} and seemingly disregarding the fact that people in love have been known, from time to time, to have sex. This is particularly prevalent among [[YuriFan yuri fandom]].

In reality the correlation between sex and romance can be anything from strict fidelity between exclusive lovers, to casual sex between friends, to dating, experimenting and anything in-between[[note]]because despite how people like their strict boundaries and categories, things rarely turn out so neatly[[/note]]. Emotions sometimes get the jump on us, and even though people tend to date each other with prospect towards a potential helpmeet, sometimes dating can become casual sex, and sometimes the reverse can be true. So yes, in RealLife people in a casual sexual relationship ''can'' find that after a while physical intimacy with another person fosters a romantic inclination, '''however''', ''this trope'' is when having a sexual relationship with another person ''will'' result in a romantic relationship, no arguing.

See also: MeetCute, RealityIsUnrealistic, AmIJustAToyToYou, CannotSpitItOut, HookerWithAHeartOfGold, {{OTP}}, {{Shipping}}, SexChangesEverything, and SexFaceTurn. The inverse of this trope is GoodPeopleHaveGoodSex.



[[folder:Anime & Manga]]
* To a degree this could apply to Guts and Casca from ''Manga/{{Berserk}}''. After helping each other, they begin treat each other more nicely and have a few nice conversations where they're not biting each other's head off. Guts and Casca are separated for a year and when he returns, not 24 hours later they have sex. Guts treats Casca as his true love from that point on. {{Justified}} in that he has serious issues with intimacy such that it's believable that he would bond very strongly to someone who was able to get past his barriers; also, [[spoiler: it's not as though they had much time to work out what an actual relationship between the two of them would be like]].
* In ''Manga/JunjouRomantica'', this was Hiroki's thought when he slept with his best friend, hoping that it would [[UnluckyChildhoodFriend convey his feelings]]. It backfired badly on him.
* In ''Manga/WildRose'', Kiri and Mikhail don't like each other at first but begin a sexual relationship very quickly because they have a supernatural bond that pulls them together. Eventually they do fall in love.
* ''Manga/VirginLove'' is about a one-night stand that ends up becoming a [[FriendsWithBenefits series of them]] which end up becoming an actual relationship.
* It's mentioned somewhere in the LightNovel/StrawberryPanic novels that Yaya would seduce girls and that 'emotions of love would grow afterwords.' [[SubvertedTrope She wonders why this didn't work on]] [[spoiler: Hikari.]]
* A JustifiedTrope in the manga version of [[FireEmblemJugdral Fire Emblem: Seisen no Keifu]], with [[spoiler: Princess Rackesis and Finn]]. They had gone through [[BreakTheCutie horrifyingly hard times]] that left them emotionally drained and barely able to return from the DespairEventHorizon, and also [[spoiler: they were going to be separated, as Fin was about to return to Lester with Quan and Ethlyn so [[MustNotDieAVirgin they didn't know if they'd ever see each other again]].]] Even more so, it's kind of a plot point later: [[spoiler: the night where Raquesis and Fin "deflowered" each other... was the one where Raquesis's eldest son Delmud was conceived.]]
* Flay Allster from ''Anime/MobileSuitGundamSEED'' (in)famously fooled Kira into this trope, by seducing him when he was weak [[spoiler: as a method of {{revenge}} since she blames him for the death of her beloved father.]] [[spoiler: Ironically, ''she'' [[BecomingtheMask fell in love with him for real]] in the end.]]
* While [[Manga/MiraiNikki Yuki and Yuno]] were already strongly attached to each other and Yuki darted back and forth about how he felt about Yuno because of being subjected to the sight of the corpses in her house. He later falls head over heels for her midway in the beginning when he decided to put to rest his suspicions about her being touched by how much she protects him. However, Yuno [[spoiler:kidnapping him in the middle of the series]] has him going back to being healthily cautious of her then went back to loving her when he told him he could [[spoiler:bring his parents back to life]] by becoming god. Come the finale he decided to have sex with her on the 27th of July rather than the 28th as predicted by the Future Diary in the beginning of the story on Yuno's phone. After consummating their love in chapter 52 (manga)/episode 23(Anime) everything comes to a head when [[spoiler: Yuki asks her if she lied to him about being able to revive his parents which she admits to lying about and apologizes.]] While that matter is easily brushed aside [[spoiler: Yuno's real trigger to starting FinalBattle of the story is confronting him about Akise's DyingMessage.]] No matter what happened in the FinalBattle Yuki cannot bring himself to [[spoiler:kill Yuno even though she makes it clear she's out to kill him so she can carry out her EvilPlan to continue repeat the Future Diary battle with Yukiteru's from other worlds.]]
* A downplayed example in ''Manga/KnightsOfSidonia''. A third gender has been created via LegoGenetics, in order to replenish decimated populations AfterTheEnd. They start out intersex, but they will turn into a male if they happen to fall in love with a female, or a female if they happen to fall in love with a male. Sex is not necessary for this transformation to happen, but sexual attraction ''is.'' This happens to Izana.


[[folder:Comic Books]]
* SuperHero Jack Hawksmoor, from superhero team ''ComicBook/TheAuthority'', had such a contract with colleague Angie, but has [[AuthorsSavingThrow erratically expressed]] the desire for a romantic relationship -- and so, for that matter, has she.
* Lieutenant [[EagleLand Steven Hudson]] has an one-night stand with biologist Kim Keller when visiting one of the ''Worlds of Aldebaran'' (''ComicBook/LesMondesDAldebaran''). He would later forbid her from having a similar relationship with a colonist, claiming it would compromise her partiality regarding the object of study (a CosmicHorror).

[[folder:Fan Works]]
* [[http://www.fimfiction.net/story/106068/1/relax/intimacy Relax]] by [[http://www.fimfiction.net/user/kalash93 Kalash93.]] While the relationship between the prostitute and her recurring client is primarily sexual and professional, their genuine warmth and affection for each other are built on real connection and understanding. This is make particularly visible in a very heartwarming way near the end, where the protagonist talks about making the prostitute his bride and taking her home with him when the war is over. Also, she won't kiss clients while on the job, but kisses him when their session is over.
* The ''Manga/DeathNote'' [[AlternateUniverseFic AU]] ''Fanfic/{{Seigikan}}'' [[{{Wimpification}} paints L as so socially naïve]] that he doesn't understand the difference.
* In the ''Series/{{Glee}}'' fic ''FanFic/HuntingTheUnicorn'', [[spoiler: Blaine]] tried to ''invoke'' this out of loneliness and naivete. [[BreakTheCutie It... didn't work.]] He's now carrying lots of emotional baggage.
* In ''FanFic/{{Shatterheart}}'' when Syaoran starts to fall for Kurogane during their FriendsWithBenefits relationship, Kurogane breaks it off because he doesn't feel that way. Kurogane, to his horror, ends up developing feelings for Syaoran regardless. Justified because they had already formed intense emotional bonds before and after they started to sleep together.

* Juno [=McGuff=] and Paulie Bleeker in ''Film/{{Juno}}''.
* Edward and Vivian in the film ''Film/PrettyWoman''.
* Played absolutely straight in ''Film/ZackAndMiriMakeAPorno''. Direct quote:
-->"Don't pretend that last night didn't mean anything to you.... We tried to fuck and instead, we wound up making love."
* Jim and Michelle from the ''Film/AmericanPie'' movies.
* ''Film/{{Her}}'': Theodore and Samantha seem like good friends (she even encourages him to go out with another woman and get laid) until one night of intense cybersex kicks their relationship into gear.
* ''Film/KillingZoe'': Zoe, who works part-time as a prostitute, falls in love with her client Zed because he makes her climax, which she believes only someone who's a good person could do. Later circumstances make this attraction more believable when Zed saves Zoe's life from his homicidal friend.

* In something of an inversion (LoveEqualsSex?), the titular [[ForgottenRealms Daughter of the Drow]] finds herself alternately saving a hunky barbarian's life and being saved by him. The protagonist develops budding feelings of friendship and love for him, but having grown up a Drow, she has no idea what they are or how to deal with them, so she falls back on a much simpler emotion that she knows and understands ''very'' well.
* The novel ''Literature/YouthInSexualEcstasy'' deconstructs and subverts this in its main message where it stresses that sex and love are two separate things, and a relationship based entirely on sex and physical attraction is not going to last long.
* Zigzagged in ''Literature/TheDresdenFiles'':
** The first woman Harry has an active relationship with, Susan, he is unquestionably in love with, and vice-versa. We're talking literally unquestionable here: true, selfless love, coupled with intimacy, [[ThePowerOfLove binds that love into a person's life force which then renders them immune]] [[EmotionEater to the feeding]] of the [[HornyDevils White Court.]] Later on, after some very complicated issues pop up that ruin Harry and Susan's lives, Harry begins a relationship with Anastasia Luccio, [[UnequalPairing technically his superior in the Wardens]]. Then [[spoiler: it is revealed that Luccio was being mind-controlled and her attraction to Harry was intended to let the traitor keep tabs on him]], and as a result Harry's immunity to the White Court is gone, further proving that there wasn't any "true" love involved.
** The relationship between Thomas and Justine develops into this. At first Justine was just a girl that Thomas cared for, and being a White Court vampire, he [[EmotionEater fed]] from her regularly. As time passed, though, he cared more and more for her, until [[spoiler: Justine saves his life from fatal injuries by letting him feed on her, which would kill her. He realized he would do this and barely manages to avoid eating too much of her life force, and in the process his affection for her became true love.]] And as a direct result of this, [[spoiler: Thomas can no longer touch Justine, as his body automatically tries to feed from hers when in contact, resulting in severe burns on his skin at best.]] Ultimately, Justine manages to figure out a way around this issue: [[spoiler: Have sex with someone else who doesn't love her, which removes the protection from White Court feedings, and then she and Thomas can be together. Rinse and repeat.]]

[[folder:Live-Action TV]]
* Done perplexingly in the ''Series/MysteryScienceTheater3000'' episode ''Film/TrackOfTheMoonBeast''. The main character and his lover interest spend one night together and ''everyone'' in the movie treats them as if they're in a long term relationship.
* In ''Series/GilmoreGirls'', Rory had a friends-with-benefits/casual dating arrangement with Logan who was a known womanizer. When she decided she couldn't handle it and tried to break it off, he, of course, offered a commitment.
* ''Series/{{Seinfeld}}'': Jerry started a sexual-only relationship with his friend Elaine Benes, based on a ill-defined set of laws. At the end of the episode, the relationship had evolved to a romantic one, described by them as "this, that and the other". The writers admit they wouldn't have done this if they'd known the show would last so long, so after the following season [[SnapBack nothing about it was ever mentioned again...]]
* J.D started a similar relationship as "sex buddies" with ex-girlfriend Elliot Reid, from ''Series/{{Scrubs}}'', a season after they broke up. When he realised he was still in love with her and decided to tell her, she broke up with him before he could, ironically because she knew that they would fall in love again and didn't want that to happen (GenreSavvy, that one).
* ''Series/{{Friends}}'': Chandler and Monica started a sexual relationship in London that they initially intended to limit to London. That fell apart after only one episode. The casual nature of their relationship fell apart after only three, and they eventually ended up HappilyMarried. Subverted in that several episodes throughout the first four seasons (when they were just friends and nothing more) had made it clear that they did love each other very much, just not in a sexual way. Apparently, introducing the sex was the only nudge needed for them to cross what was clearly (for them) a blurred line between platonic and romantic love. There's also the fact that previous seasons had both of them struggling not to get attached to people they slept with: In one episode Chandler started a FriendsWithBenefits relationship with a woman only to realize he needed more and call it off, while Monica tried to hook up casually with her ex-boyfriend only to fall in love with him again. So both of them were doomed to be this trope from the start really.
* Averted in ''Series/DoctorWho''. There have been several occasions in recent years where the Doctor's companion has fallen in love with the Time Lord, and a couple of occasions in which he reciprocates. Yet with the exception of innuendo from River Song, there is never any indication of sexual relations. Creator/PeterCapaldi is on record as describing the current (as of 2015) relationship between the Twelfth Doctor and Clara Oswald as "an old-fashioned romance". Love is unambiguous in their relationship, with Clara at one point even challenging the Doctor into action with the words "If you love me in any way, you'll come back" and revealing intimate knowledge of the Doctor that most prior companions have not possessed. The Doctor has also expressed (in his own way) devotion to Clara. At one point (in the episode "Last Christmas") Clara directly states that the Doctor is the only man she'd imagine marrying. And the finale trilogy of Series 9 strips away any illusions that Clara and the Doctor aren't in love with each other (to the degree that the entire universe is threatened by it). Yet nothing sexual has ever been implied in the series, pushing against the trope that suggests love and romance (implied or direct) must involve sex. Instead, as shown several times in both Series 8 and 9, Clara and the Doctor substitute action (saving the world, being chased by Daleks, the adrenaline rush of near-death experiences) for physical intimacy.
* In ''Series/{{Torchwood}}'', Owen began having uncompromised sex with his colleague Gwen Cooper. This sexual relationship subverted the sex equals love idea when it broke down due to Owen falling in love with someone else.
** Played straight with Jack and Ianto. Their relationship does turn into mutual love, but Ianto's more openly attached.
* Lawyer Brad Chase, from ''Series/BostonLegal'', had an agreement centering around sex with his colleague Denise, described as "Friend With Benefits". They are now engaged, at his request.
* Doctors Chase and Cameron, fellows of doctor Gregory ''Series/{{House}}'', started having casual sex at Cameron's suggestion. Cameron later broke the relationship off when Chase developed feelings for her, but they did end up together at the end of the season (3) and married at the end of season 5.
** [[spoiler: And divorced halfway through season 6.]]
* In an episode of ''Series/{{Farscape}}'', Chiana tries to convince Crichton to try this strategy on Aeryn: "You gotta go fast with the body, slow with the soul." He doesn't go for it.
** Rather sadly, D'Argo believes in this trope and Chiana...doesn't.
*** Of course, D'Argo is a member of a ProudWarriorRace, and with those races, either sex is a marriage proposal, or it never means anything ever, with no gray area in between.
* Subverted into ''Love Equals Sex'' between Elizabeth and Lawrence of period drama ''Series/UpstairsDownstairs''. They're married, but he's an aloof poet and refuses to touch her. It doesn't help matters that when she attempts to get an annulment on grounds of impotence, she's [[TheBabyTrap pregnant with someone else's kid]].
* Subverted in ''Series/SexAndTheCity'' when Carrie tries to go on actual dates with her "fuck buddy," convinced that their great sex has to mean a great emotional connection as well. It doesn't.
* Barney fell in love with Robin after having slept with her in a season three episode of ''Series/HowIMetYourMother''. He didn't actually ''realize'' that he was in love with her until he had a near-death experience, though.
** Also played with in a later episode: After Ted and Robin decide to be FriendsWithBenefits, Lily [[GenreSavvy warns them that it's a bad idea, and that their arrangement will wind up with someone getting hurt.]] Ted and Robin are both fine--they never actually fall back in love, although they ''both'' worry about the fact that they somehow automatically start doing little lovey-dovey things like a kiss goodbye every morning. In the end, the person it winds up hurting is ''Barney'', who's secretly in love with Robin. When Ted figures this out, he immediately breaks it off with Robin and allows her to think it's because he's worried about this trope (since Ted is notorious for being a romantic sap), to preserve Barney's secret.
* After deflowering [[Series/GossipGirl Blair]] in the back of his limo, Chuck found himself unable to sleep and with a sickening fluttering feeling in his stomach. Blair correctly diagnosed them as butterflies and demanded they be murdered. Instead he began pursuing her and eventually she fell in love with him too.
* ''Series/BuffyTheVampireSlayer''. Anya claims to want to have sex with Xander only as a way to get over him. Sure enough once they do have sex, she wants to make the next step so they start dating in the very next episode and end up having a long-term relationship.
** Averted with everyone Faith has sex with. At one point in Season 3, she takes Xander's virginity. Nothing else comes of it (in fact Xander nearly gets killed by Faith after assuming this trope [[ItDoesntMeanAnything makes them more intimate than they actually are]]). In Season 7, she and a guy do hook up. They break up in-between seasons and he's PutOnABus. Also averted with Buffy's fling with Parker, though that was him being a dick and her taking it really badly.
** Averted in Season 6. Spike hopes that his sexual relationship with Buffy will eventually lead to his love for her being returned. Buffy repeatedly insists ([[BastardGirlfriend sometimes quite violently]]) that there's nothing between them except sex, and for Spike to even call her "luv" or "my girl" is a guaranteed BerserkButton. After Buffy dumps him, Spike tries to rape her in the belief that she did feel love during their rough sex and Buffy is simply in denial.
* ''Series/{{Angel}}''. Wesley and Lilah have very disturbing sex-only encounters for a while, eventually placing a bet on who would be first to call it a "relationship." Wesley loses. It's shown that sex ends up causing emotional attachments and complications for both of them, with each of them trying to "save" the other: Wesley had hoped to save her from evil and Lilah had hoped to corrupt him to evil. This does not end well.
* In the ''Series/DegrassiTheNextGeneration'' movie, ''Degrassi Takes Manhattan,'' Spinner and Emma decide they are meant to be together after a couple days of friendship, an AccidentalMarriage, and one night of sex. The really crazy thing? Both of them were too drunk to actually remember said sex.
** Well to be fair, they did actually spend a few more days having sex before deciding to stay married for good.
* In the first episode of ''Series/TheLWord'' a character is commenting on the fact that almost all lesbians in a given community have done each other eventually. This leads her to conclude that we are all connected by "love."

* Psychostick song ''Orgasm Equals Love'' parodies this trope.

[[folder:Professional Wrestling]]
* Wrestling/JimmyJacobs was madly in love with The Lovely Lacey, but she only viewed him as a tool. Lacey loved Wrestling/ColtCabana, and was having sex with him too, which Colt wasn't afraid to rub in Jimmy's face. Then Colt dumped Lacey, after he got tired of sex because he didn't love her. Jacobs kicks Colt's ass, many events transpire, Lacey "rewards" Jacobs for all his work and suddenly she is madly in love with him. Jimmy, perhaps recognizing this trope, wants to slow down to ensure their relationship isn't based on lust. It's not, seeing Jacobs finally succeed in the improbable task of taking out BJ Whitmer at [[PyrrhicVictory the cost of his ability to walk]] is what changed Lacey's tune, but sex is what led her to openly declare her love for Jacobs and it's also what broke them apart when Lacey, recruiting for Jimmy's Age Of The Fall, ends up falling for and sleeping with Wrestling/AustinAries, who kisses and tells.[[/folder]]

[[folder:Video Games]]
* Largely averted in ''VideoGame/DragonAgeOrigins''. The Player Character can engage in, ahem, relations with a number of [=NPCs=] without love entering into it. Somewhat played straight in that two of the game's main love interests Zevran and Morrigan will have casual sex with you, but will eventually fall in love with you if you continue the relationship. (You CAN end the relationship after one encounter, however.) The other two love interests, Alistair and Leliana, will only invite you to bed once they've developed feelings for your character.
** It can be said that three of the four love interests will demand fidelity from the PC. (Zevran is cool with you jumping into bed with whoever you like, so long as the other characters aren't getting too attached.)
** Morrigan doesn't want you sleeping with others long before she even ''understands'' the concept of love. Why? Because Morrigan doesn't like to share her things.
* Played straight in ''VideoGame/DragonAgeII'' with Isabela. Her relationship with Hawke started out as an amusing diversion, yet three years later she's ready to admit that she's falling for Hawke.
** Played with a little bit with Isabela actually, since the sexual element of the relationship starts something like three or four years before she will come forward about bringing feelings into the mix. And even then that [[YouLoseAtZeroTrust only happens if the player has a good friendship or rivalry with her.]] Otherwise, it really will [[FriendsWithBenefits just be for sex.]]
** Averted with the other three romanceable companions, however.
* Played with in several ways in ''VideoGame/MassEffect2''. About half of the romance paths end in a sex scene, but three of them are aliens, and their [[BizarreAlienBiology bizarre biology]] means they have to be really careful, and a lot of time is spent psyching themselves up. Tali is initially really nervous but later says that it was WorthIt, while Garrus and female Shepard start out with the plan of having a FriendsWithBenefits relationship, but as things progress, it's obvious that Garrus really ''does'' have romantic feelings for Shepard -- ''before'' they have sex. So they're more of an aversion than anything else. Completely averted with [[AxCrazy Jack]]: fairly early on, you can have casual sex with her, but once you do, she won't talk to you again. Turning down the sex leads her to slowly come out of her shell, and the ending of her romance implies kissing, but no sex.
* In ''VideoGame/TeamFortress2'', the official comic "A Cold Day In Hell" introduced Heavy Weapons Guy's three younger sisters, who spent their entire lives thus far locked in Heavy's cabin, in an attempt to keep them safe from the Communists trying to kill them. As a result, the now-grown sisters have gotten a little desperate for sex, and Zhanna, the oldest, propositions Soldier for sex almost immediately upon seeing him. The two hit it off almost immediately, and as of the next comic, "Blood In The Water", Zhanna and Soldier are an engaged BattleCouple, with Soldier even slicing the ears off his enemies in an attempt to make his fianceé a necklace.

[[folder:Visual Novels]]
* Averted in VisualNovel/{{Canvas 2}} twice in Hagino's route. [[spoiler:First, they start to have sex at the end of a date before really loving the other, then stopping. Later, there's an optional sex encounter with the woman Hiroki used to hate and still doesn't really like.]]
* This is one of the issues behind [[spoiler: Yasu]] in ''VisualNovel/UminekoWhenTheyCry''. [[spoiler: Because of Yasu's mutilated sexual organs [[AmbiguousGender he/she]] is unable to have sex and is afraid that the persons his/her alternative selves/personas (Shannon, Kanon, Beatrice) love will leave him/her if (s)he reveales the truth.]] The series never comments upon whether [[spoiler: Yasu]] is right or not but that's not the point, the important part is that those feelings exist and is a big part of [[spoiler: Yasu]]'s problems.
* Inverted and (possibly) played straight in Emi's path in KatawaShoujo. Emi is [[spoiler: afraid to get emotionally close to her boyfriend Hisao, even after they've started having sex, because she's afraid of being hurt like [[DisappearedDad before]]. Hisao is rather frustrated and refers to their relationship as [[FriendsWithBenefits "friends who like to fuck"]], and to ''actually'' approach Emi in the emotional sense, he will have to work ''hard''.]]
* In VisualNovel/TrueLoveJunaiMonogatari, ''the'' sign that a girl is in love with the PlayerCharacter is that she'll be willing to have sex with him.

[[folder:Web Comics]]
* ''Webcomic/PunchAnPie'' subverts this one step forward: two characters in the midst of some weirdly flavored UnresolvedSexualTension finally have sex (and presumably continue to do so)... but they're still not sure if they're even ''in a relationship'' yet.
* One ''Webcomic/GirlsWithSlingshots'' arc had Thea discovering Angel was sleeping with another woman. When Thea calls Angel out on this, Angel states that Thea was never her girlfriend. Thea is hurt by this because she assumed that the pair of them having sex in the back room of the bar all the time meant they were a couple, honestly baffled when Hazel asked.
---> Hazel: Did she know she was your girlfriend?
---> Thea: You act like she doesn't know what a girlfriend is.
* The trope is lampshaded in [[http://wapsisquare.com/comic/your-auras/ this]] ''Webcomic/WapsiSquare'' strip, when Tina explains that sex in a relationship does not necessarily mean emotional closeness.