You mean have sex with them and not be in love? Or mutually fuck around with a friend on occasion to have fun? Those are different. Yes there are a ton of straight guys who hook up discretely via Grindr, Craigslist, BBRTS.com, etc. to get a blow job or bust a nut in a tight ass. Maybe they're girl won't do anal. Maybe he likes looking down upon a "fag" to degrade him or make him his bitch, somehow that domination gets some straight guys off. Maybe they're just super horny and haven't had any luck with girls when they need it so they try guys. SO MANY REASONS. Tricky subject. Not two minds of men are alike. I absolutely can't get hard or aroused to the thought of a girl, let alone a picture or physical encounter. VERY repulsive actually.
If you are asking if you can fuck someone and not develop feelings for them, that's another story. If you have a really close friend fucking them will most likely make it awkward. If it's their first time or your first time, people tend to develop feelings for their first. Or if they make you have an ultra intense orgasm.
I wonder how many straight guys have a gay friend they casually fuck around with on occasion and don't let their experiences and secrets cause problems. That's how porn is depicted. Especially hidden cam anonymous hookup clips. Or roommates. I personally don't think if the guy can be entirely straight if he's messing around with another dude. Just as I can't mess around with chicks due to the intense repulsion. Seriously pussy looks like a crime scene/ axe wound and wouldn't be surprised if they had retractable teeth. I can't even stand the word.