You either misunderstand the premise, or your logic is faulty.
“Lots of people have sex without falling in love” actually supports my assertion.
Here, from a real world perspective. Since I’ve been involved with recruiting male models for porn websites, I’ve gotten to know a lot of guys who keep a pretty clear dividing line between sex and love. Since 90%+ of the population is straight, 90%+ of the guys I work with are straight. But women don’t buy porn, so if a guy is going to make a living in adult work he has to appeal to a male audience. What all this means is that most of the actors in gay porn are actually straight guys, doing a job for money.
Here’s how it usually works: I see a guy I think has some potential as a model. I give him a business card. If he contacts me, I get him a gig doing a solo video shoot, like a male stripper/centerfold video. Basically a modeling job . . . with a money shot. Invariably, once a guy’s done that, he gets other offers: we’ll pay you $X,XXX to have sex with another guy on camera. About half the time, the guy needs the money enough that he’ll give it a try. I tell them to think of it as an episode of Fear Factor. Look at it this way: if someone bet you $50 to eat a worm, you’d probably do it. So, for $5,000 . . .
Most of them find it’s not that big a deal; it’s a job. There are people who get $15 an hour to work in a sewer or shovel elephant shit. Surely you can go through the motions of pretending to enjoy having sex with the “wrong” gender for a couple grand an hour, no?
True, some of the guys discover through this process that they’re bi. (So far I haven’t had anyone that I know personally decide they were all out gay, unless they already knew it.) But the vast majority of the guys that I’ve worked with in this context simply do it as a job, then go home to their girlfriend or wife. The most successful gay porn star that I personally know–a pretty big name, FWIW–has a wife and two kids. Not that that’s any kind of proof, but I’ve known him for 9 years. He’s still 100% straight, but he’s become a pretty good performer. An actor.
That’s the distinction I was trying to make: what you do with your genitals doesn’t determine your orientation. There are, as you yourself point out, more than reason to “share” your genitals with another person; it’s not always love. Who you share your love with, though, that’s what counts as far as orientation. If you have sex with guys for money, but you only fall in love with women–or you have to fantasize with women in order to fake sex with guys–then you, yourself, are straight, even if you perform gay sex for a living.
Bottom line: sexual orientation is about who you are, not what you do.
