Cheating on a partner really isn't about sex.
Cheating
"It didn't mean anything..." How often has that been said by someone caught cheating?
Can a sexual encounter not mean anything? I don't think so.
Some think if both parties are willing to use the other as an object, and understand they're using each other only for passing satisfaction, it's possible for them to have a sexual encounter that doesn't mean anything beyond the pleasure. But a sexual encounter can't be meaningless if either party engages the other as a person or if either has a long-term partner because then there's betrayal of two kinds.
Betrayal of a long-term partner has little to do with sex. It has to do with intimacy. In a significant relationship we establish an ongoing intimacy; we make love all the time, as Robert Parker puts it. Eating together, taking a walk together, shopping together; all of that is as much making love as having sex. It's that intimacy that we betray when we cheat because we make love with another, even if for a short time.
But we also betray short-term partners, even one-night stands. The reason is that human psychology being what it is, we bring too much personal baggage to sexual encounters with others we engage with as persons, however briefly. Even if we think we're treating a short-term sexual partner as an object, we're likely not because very few people can manage to completely objectivize another person. So we give away too much and make ourselves vulnerable, we establish a brief intimacy that goes beyond seeing one another naked and sharing bodies. We do so from the moment we start flirting.
Trouble is, not many can have sex without preliminaries. A measure of intimacy must be established, however brief or false. Even sex with prostitutes involves pretended intimacy. So not only do we betray the intimacy we share with our long-term partners by cheating, we betray our short-term partner by establishing a bogus intimacy with them.
For cultural and evolutionary reasons, women understand all of this better than men. That's why men seem to think they haven't cheated on their partners if they stop just short of actual intercourse. What they don't appreciate is that intercourse is just the last stage in an intimate encounter. Often it's less important than what we reveal and learn in the process of getting to that point.
Cheating isn't about sex; it's about intimacy.
