Sex for fun? No attachment.

I don't understand how people can have sex for fun they do it with multiple people they don't even know and they like it that way. Sex to me is so emotional and what you do when your in a relationship. I could never have sex with a random person. I need to be in a committed relationship. If your one of these people that have sex with randoms tell me how you can have sex with someone your not in a relationship with.