I know this is hard to hear. Because she must be amazing — or must seem amazing, anyway — if you’re considering this question at all. If she was a reasonably attractive, moderately interesting person, this wouldn’t be an issue whatsoever. You’d just tell her to eff off, feel a very mild pain, make some regrettable sexual decisions, and continue living your life.
But this girl is different, for whatever reason. You just don’t want to let her go, even though you feel terrifically humiliated, and your mind is filled with images of how, exactly, you would murder the dude in question (I’d go with suffocation by Silly String). Probably, there’s a peculiar way she smiles at you that makes you forget that being alive was ever difficult. She probably knows how you like your coffee and she brings it to you every morning. You have so many little in-jokes and routines that you don’t know how you would communicate with anyone else.
And she assures you that she’s still that person — that this was just a one-time thing, a mistake. She swears, sincerely, that she didn’t really want to cheat on you. The deception is temporary. It’s not who she is, deep down. Maybe she used the classic phrase so often deployed in discussions of cheating, which is, “it just happened.”
Unfortunately, that’s not a real thing. That’s not how cheating works. In fact, it’s exactly backwards.
The truth about cheating is that we all want to do it, on some level, almost all the time, and we don’t cheat by deciding not to, every single day.
Think about it. How many times, per day, do you mentally sort people into the categories of ‘would touch naked’ and ‘would not touch naked’? It’s probably a high number, unless you’re an asexual living on an iceberg. (Respect to my arctic asexual readership.) Even if you know it’s stupid, you can’t help but wonder whether your neighbor is secretly your dream girl, even though you’ve never spoken — something about the way she styles her hair makes it seem like she’d really, like, understand you, right? Our minds have a really annoying way of constantly wondering whether there might be a better deal out there.
And there are much more serious manifestations of this tendency that I’m sure you know all about, as well. Like, chances are, there are between one and three women in your life who you just Don’t Hang Out With. That pretty person you get along with just a little too well. Your attractive co-worker who always complains about how there aren’t any interesting single men, right after lavishly complimenting your new haircut. Or your ex from far back enough that you can’t remember why you ever broke up, whose new profile picture makes you breathe heavily.
Every day, you look in the mirror and you say, “Today I’m not going to hook up with any of those people.” Congratulations! You’re a good guy. Someone should give you a prize. You’re really behaving tremendously well. Remember when that co-worker invited you out for beers, and you hesitated — she just seems like a total freak in the best way — but you said no? That was great! And when that ex started sending you funny Facebook messages late at night, but you shut it down? Bravo.
You avoided danger. You saw what was coming, and you said no. Even though there are days when your girlfriend is irritating the hell out of you, you keep it together. You realize that the short-term gratification of random female attention is less rewarding than sharing your world with somebody.
Like it or not, your girlfriend faces the same dilemma. She has the same temptations. That Junior VP in her office with a closet full of sharp bespoke suits and a beguiling sarcasm? She’s thought about that, for sure. She sees hot guys coming and going, and briefly questions her commitment to monogamy. But, unlike you, she said “yes” to that very tempting train of thought. Whatever the circumstance was in which she met this guy, she knew she was tempting fate, and she did it anyway.
Again, I know it’s hard to hear, but it’s simply realistic to say that there were a million tiny moments of decision between the moment when she kissed you goodbye and she kissed that guy hello. At every step, she knew she was getting closer and closer to cheating on you. And, at each step, she was like, “Yeah, OK, that seems like a reasonable decision.” She was like, “I’m going to wear this sexy outfit when I meet up with this random male friend, just because I like wearing sexy outfits, because that’s totally normal.” She was like, “I thought we were just getting coffee, but, really, what’s the harm in a drink or two.”
Maybe she never thought, “Oh boy, time to cheat on my perfect boyfriend.” She just found this dude’s attention flattering, and she found the whole thing exciting. So she ignored the voice of reason in her head — which was almost certainly there — telling her that this was a bad idea.
You may want to believe that this was her one moment of infidelity. And that’s vaguely possible. But thrill-seeking, unconscientious people tend to remain that way. She’ll see other guys, and feel the intoxication of flattery, and she’ll probably be at least strongly tempted to screw you over again. She’s just a human, unfortunately, and humans tend to change their behavior only when it’s absolutely, totally necessary.
And, by the way, if you don’t let her go, you won’t tell her that it’s absolutely necessary to change her behavior. You’re telling her that if she cries, and says she regrets it, and reminds you of what you shared back when the relationship wasn’t a 30-car pileup, you’ll forgive her. That probably won’t make her change. She might change someday, but unfortunately you can’t control the circumstances that will bring that about.
This is going to be a hard talk. She’ll probably tell you that she still loves you, over and over again, that she loves you more than ever. That may be true. But do you really need that kind of love?