I get the porn thing definitely. Porn misses the tactile aspects of real sex as well as sweat, smelliness, etc. So it can feel more enticing to have sex on our own terms, in a less awkward fashion too: no farts, no "could we switch positions?", no over-exhaustion. Also without the potential embarrassment of losing your erection, cumming too quick, etc. which are all natural things that happen every now and then.
Also the way sex is depicted in porn is super hetero-normative: penetration is the end all be all and when the guy cums: sex is over. If penetration is all there is too, then its seemingly more important if the penis is as big as possible and that the man is the one who produces pleasure - which is a lot of pressure, if you ask me, when 99.9% of female orgasms are clitoral.